language-overview

Individuals with Down syndrome have specific speech and language impairments

Introduction

Speech and language skills are an area of particular difficulty for most children and adolescents with Down syndrome, even though they are keen to communicate right from infancy and usually have strengths in non-verbal communication skills such as gesture and sign. Spoken language skills are usually delayed relative to the children’s non-verbal ability and this suggests a profile of specific language impairment. This should be a focus for targeted and intensive intervention throughout infancy and childhood, as it is in other language impaired children who show a gap between verbal and non-verbal abilities.

There has been a considerable amount of research effort over the past thirty years focused on understanding the speech and language profile associated with Down syndrome. In the last ten years there have been many important papers, [1-7] book chapters [8-21] and books [22-24] published on speech and language development in individuals with Down syndrome, and the reader wishing to read the literature in more detail is advised to consult these. These publications have all contributed to an increased understanding of the language learning needs of children with Down syndrome. There is now considerable agreement among the experts on the principles which should guide effective interventions. [TODO: references 1], [TODO: references 4], [9-12], [24-27]

This module explains speech and language development, highlighting the key findings from research into

  1. the processes and influences on speech and language development in typically developing children
  2. the specific speech and language difficulties of children with Down syndrome and their possible causes
  3. effective interventions

This module should be read before using the accompanying practical modules.

Speech and language skills are central to social interaction

The importance of learning to talk

Learning to talk is the most important thing that children do. It is central to all other aspects of their development. It is critically important for social and emotional development and for the development of cognitive or mental abilities. This is a theme that will be explained and reinforced as the module develops.

Speech and language skills are central to social interaction

Being able to talk allows children to gain control over their social and emotional world. Talking enables children to ask for what they want, to share experiences, to understand what is about to happen, and to express themselves when they are hurt or upset. In short, talking enables children to relate to others.

By the preschool years, being able to communicate enables children to play together, to share and to learn together. In school and throughout life, communication underpins the development of friendships, the sharing of experiences, supporting one another, and negotiating our way through the world - shopping, travelling and working.

Speech and language skills are central to mental ability

Being able to talk also underpins the development of mental abilities

It is important to note that word learning begins in the first year of life and continues to old age. Words are knowledge. Each new word learned is a concept learned and the rate at which words are learned reflects the rate at which we are gaining knowledge about our world. As language skills develop, words become a tool for thinking. Once children begin to string words together, words take over as the most powerful way to think and reason and remember - we do these things most often as silent speech in our heads.

The human brain has clearly evolved to be very efficient at developing spoken language and using language as a tool for other mental processes, such as working memory.

See also:

Working memory is the short-term memory system that supports the initial processing of incoming spoken and visual information as well as current mental activities such as reading text or adding sums. It is typically a speech-based system and its efficiency increases as children’s speech processing and speech production abilities improve. Speech and language skills also influence, and are influenced by, progress in reading skills.

In summary, talking underpins our mental development and our ability to interact with the world around us. Talking is not the only way to communicate and we all use many non-verbal means to express ourselves in addition to words, however words are the most powerful form of communication for social life and for learning.

This module focuses on the development of spoken language as almost all individuals with Down syndrome will use speech as their main mode of communication after five years of age. Signs may be used as a bridge to teaching spoken language skills but these signs should be ‘keyword’ signs used to augment spoken words, they are not taught as an alternative language. Signs may continue to be helpful throughout life for many individuals with Down syndrome to support their spoken language, as their speech often remains difficult to understand.

The skills and knowledge needed for talking

A complex range of knowledge and skills interact to give us our ability to communicate by talking. These can be considered under three main headings - interactive communication skills, spoken language knowledge and speaking. Spoken language knowledge can be further subdivided into vocabulary and grammar. In [Table 1] the terms that professionals may use for these different aspects of talking are included in brackets.

Table 1. The skills and knowledge needed for talking
Interaction | Spoken language knowledge | Speaking |
Non-verbal skills | Vocabulary | Grammar | Speech/motor skills |
Smiling, eye-contact, taking turns, initiating a conversation, maintaining the topic\

Body language
Facial expressions
(pragmatics and discourse skills) | Building a dictionary of single words and their meanings (lexicon and semantics) | Learning the word ending rules for plurals, tenses and word order rules for questions, negatives, (morphology and syntax) | Learning to make speech sounds and to produce clear words with correct stress and intonation (articulation, phonology and prosody) |

At any age, children’s progress in all areas (i.e. in interactive communication skills, vocabulary knowledge, grammar knowledge and speech skills) always need to be considered. These skills are acquired over a period of years from infancy through primary and secondary school and a great deal is known about the processes that influence their development in typically developing children.

Table 2. The typical timetable for learning to talk
Age | Communication | Vocabulary | Grammar | Speech |
Infants (0-12 months) | Crying\

Eye-contact
Smiling
Listening/looking
Vocalising - coos
Turn taking
Joint attention
Gestures | Understanding some words | | Babble
Babble tuned to native language | | 12-24 months | Conveying an increasing number of meanings in words | Beginning to say words
First 10 words
First 50 - 100 words | Begin saying two words together | Initial consonants and vowels developing
Words not very clear/intelligible | | 24-36 months | Initiating conversations | 300 words
Rate of word learning increases (25 words per month) | Three and four key words together
‘telegraphic’ sentences
Grammar begins | Consonant, vowel and word production improve in accuracy | | 36-60 months | Repairing conversations when not understood | Vocabulary learning continues to accelerate | Increasingly correct sentences | Consonant and vowel production continue to improve in accuracy | | 5-7 years | Learning to continue narratives,
Taking part in longer topic related conversations
Telling stories
Requesting clarifications - . What?, Where? | Average vocabulary of about 2000 words at 5 years | Correct syntax being mastered
More difficult prepositions
above, below,
conjunctions - because,
comparatives - ‘longer than’ | Blends improve
Speech intelligible | | 7-16 | Developing social use of language further - social small talk
Taking account of listener’s knowledge - know how to provide appropriate amounts of information for person or social situation
Give longer explanations or instructions
Telling jokes
Recounting experiences
Discussing attitudes and beliefs, with rationales | From 7 years 3000 new words learned each year
50,000 words or more at 16 years | Grammar steadily extended to include passives and other features such as
‘not only but also’
‘however’, ‘therefore’
Many of these features are learned and used first in reading and writing and then in speaking | Speech rate and speech clarity continue to improve, influenced by reading |

Comprehension and production of language

[Table 2] provides a guide to the way in which progress in each area relates to ages and to stages of development in typically developing children. The table describes the milestones for children’s spoken language skills in each area. Most children will understand these actions, words and grammar in everyday communication earlier than they are able to use them in their speech. Therefore, when assessing children’s language skills, production and comprehension of vocabulary and grammar are assessed separately.

The range of skills required for individuals with Down syndrome to communicate are no different from the range of skills employed by anyone else. Unfortunately, a number of difficulties with the skills required for speech and language are associated with Down syndrome. Promoting these skills and helping children with Down syndrome to overcome these difficulties is clearly fundamental for all aspects of their social and mental development. The way in which each of the skills develop in non-disabled children is discussed in the following section to set the scene for understanding the difficulties faced by children with Down syndrome and ways in which they may be reduced or overcome.

Learning to talk is an everyday activity

Learning to talk is an everyday activity

Children learn to talk because they want to communicate. Communicating with gestures in infancy leads to communicating with words and sentences. Children learn to talk as they take part in all the ordinary, everyday communication that they experience during their waking hours. The quality and quantity of the language that they experience as they are talked to each day influences the rate at which children progress with learning to talk. [28-30]

Parent’s talk styles influence children’s progress

Parent’s influence on child talk

Using choices and explanations was better:

Adapted from Hart and Risley [30 p.149]

Longitudinal research by Hart and Risley [TODO: references 29], [TODO: references 30] indicates that the amount and quality of talk that typically developing babies are exposed to each day varies considerably in different homes. The more children were talked to, the faster they expanded their vocabulary. The children who were talked to the most had the highest Verbal IQ scores at 4 years, also supporting this author’s argument that language learning is fundamental to the development of cognitive skills or mental abilities.

Parents who were more effective language teachers

Adapted from Hart and Risley [30 p.149]

Verbal IQ was specifically influenced by the amount that parents participated in activities with their children and included their children in conversation as they went about daily chores, by the total amount of words and range of different words that parents used with their children, by parent’s responsiveness to their children’s attempts to initiate communications and by the way in which parents responded. Positive response styles included extensions and expansions of the child’s utterance, which help to teach grammar. They also included a style which asked, rather than told, children to do things.

The link between language learning and intelligence

‘’A vocabulary growth curve provides a direct and continuous measure of a child’s intellectual functioning … The growth of the vocabulary in use directly reflects the increasing complexity of symbols a child learns to manipulate relative to everyday experience. We did not need to infer cognitive growth from monitoring a child’s periodic performance on a small set of standardised test items: we could measure learning as it was happening’’ - Hart and Risley [30, p.16]

Emotional style turned out to be particularly important as the children of parents who regularly used a negative style, that is, saying ‘’no’’, criticising the child and prohibiting activities made much slower progress with their language development than the children of parents who regularly had a positive style and praised, encouraged and conveyed delight at their children’s efforts. Children also learned to talk like their parents, using orders and being negative and bossy in style or using explanations and asking politely, depending on parent style.

Play activities and book reading

Studies have shown that, while including children in conversations throughout the day is important, the language that parents use when joining in toy play activities and reading books with children provides the richest sources of language experience for their children.

Children learn, and later use, the language that has been addressed to them in specific contexts repeatedly, as is illustrated by the early use of ‘bye-bye’, ‘all gone’, ‘more’ and by the learning of responses in games and from singing action or nursery rhymes. Learning from regular repetition in social situations and from games is probably even more important for children with language learning difficulties.

Influences on the rate at which a child learns to talk

Social learning with other children

As children move beyond the family to preschool and school settings, the opportunities to communicate with a wide range of partners develop. The quality and quantity of these social opportunities, particularly with peers, will also influence all aspects of speech and language development.

Learning to talk is a process starting in infancy

Becoming an effective communicator

The typical infant is laying the foundations for learning to talk in the first year of life. In the first few months, babies learn that communicating is fun and that when communicating they have the full attention of another person, child or adult. They learn this from their earliest smiling at about six weeks of age. When someone looks at and talks to a baby, they usually looks and smiles. Later, when we are talking to each other, we usually look at the person talking to us, that is, we make eye-contact - we look and we listen.

Early non-verbal communication

We also take turns in the conversation, listening and then talking. Babies are usually showing turn-taking skills by 7 or 8 months of age, when engaged in babble games. The baby is quiet and looks, while their communication partner coos or talks to them and then they takes a turn and babbles, gurgles or coos in reply. We communicate in a variety of ways, using facial expressions, tones of voice and gestures, for example. Babies have to learn to interpret and to use all of these if they are to be good communicators.

Foundations of clear speech

Babies are listening and practising sounds as they babble and they are getting familiar with the sound patterns (prosody) of sentences, that is the ‘lilt’ or intonation of the language - how words or parts of words and word endings are stressed to alter meaning and how voices rise at the end of questions, for example. This sound pattern of sentences is thought to help the child to learn grammar and they are sensitive to prosody from the first year of life.

Starting intentional communication

Most babies use gestures to communicate before they use words. They point in order to say ‘Look’ or ‘What’s that?’ They wave ‘bye-bye’ and hold up their hands to say ‘pick me up please’. This is a natural stage, when gestures are used before the baby can say the word. Using gestures, babies learn that they can influence the behaviour of those around them in their world. Babies and toddlers use gestures for a range of communicative activities (or functions). A list of the different uses of gesture that babies show is set out in the side box.

This is an important stage as the baby is now developing different gestures to signal different and specific meanings and this is referred to as the start of intentional communication. The baby is showing increasing understanding of communication and language, and they are becoming a more effective communicator.

Until the baby uses gestures for ‘’Look’’ or ‘’What’s that?’’ or ‘’Give me’’ they are unlikely to say the words. Gestures can be used in response to an adult offering or pointing or commenting and they can be used first by the baby to initiate the interaction with the adult. Initiation is an important step as it really does show the baby is intending to communicate.

Lifelong skills

These non-verbal skills - smiling, eye-contact, turn-taking, facial expressions, tones of voice, gestures such as pointing and waving- are all important aspects of communication to be mastered as the baby moves towards talking. They continue to be part of the communication exchange whenever we talk to another person and so remain important throughout life.

Building a vocabulary

Comprehension before expression

Basic skills necessary for language development

The next step towards being a competent talker is learning to understand and then say words, to build up a vocabulary of words. Babies begin to understand the words that they hear spoken to them and around them because the words are referring to things that they are seeing, hearing or doing. Each day, parents talk to babies as they pick them up, feed, bathe, change nappies, go for a walk, or take a ride in the car. As babies hear the same words used day after day, in the same contexts, they begin to learn their meanings. The first 50 to 100 words that babies say are similar in meaning in all cultures, because they are all engaged in similar daily living activities. Between 12 to 18 months, young children begin to talk. They begin to say some of the words that they understand, to use them to communicate.

Therefore, in order to progress with talking at a typical rate, a baby must have good hearing, be able to link words with their meanings during everyday experiences of talk, and have normal speech production abilities.

Joint attention

Joint attention is important for language learning

Babies are very active in setting up their own language learning situations. Around one year of age, they can initiate ‘joint attention’ sessions. These are situations when the baby and their carer are attending to the same object or activity, for example, both looking at a toy or at a car passing. The carer, whose attention to the toy or the car has been established by the baby holding it up or pointing, talks about the toy or the car. The more of these ‘joint attention’ sessions the baby experiences, the faster they will pick up the meanings of words. [31-36]

Adults can also set up these joint attention sessions by drawing the baby’s attention to an object or activity. Research indicates that the more children are talked to in these situations, where they can ‘see what you mean’ the faster they learn to talk. The more children are talked to in this way, the more opportunities they have for learning a wide range of vocabulary. Some adults do this naturally, that is, they tend to talk to the baby in this way while going about ordinary activities together during the day. Others are rather quieter and do not talk to the children in their care to the same extent. These differences in the number of joint attention episodes children experience affect the rate at which children learn early vocabulary. [37-39]

More vocabulary - new words through life

Vocabulary learning continues through childhood

Vocabulary learning starts in infancy and continues throughout life. Each new word that the baby learns to understand and then to say represents a piece of knowledge about the world. We have words for just about everything that we know something about and the size of our vocabularies reflects the extent of our world knowledge. If a baby is learning words more slowly, then they will be learning about their world, and the things and people in it, more slowly than the child who picks up words at a faster rate.

Stages of language development

There is a link between the rate at which a child is mastering the language of the community and the rate at which they can develop knowledge and mental abilities such as reasoning and remembering. In the author’s view, significant speech and language delay is bound to lead to cognitive delay for any child (for a more detailed explanation and evidence for this view in relation to children with Down syndrome see Buckley [TODO: references 40]).

Two word speech

Once babies have mastered about 50 words (on average at about 19 months), they begin to join them together to communicate a wider variety of meanings, such as ‘big dog’, ‘mummy’s car’, ‘daddy gone’, ‘more drink’, ‘cat sleep’. First vocabularies are made up of mainly nouns, verbs and adjectives. [TODO: references 43]

Expansions and extensions are important for language learning

These are the content words that carry the main meanings of the sentence. Parents naturally expand and extend their children’s utterances at this stage, for example, by saying ‘’Yes, that is a big dog’’ when the child says ‘’big dog’’ or ‘’That is not Mummy’s car, it looks like it. It is the same colour but it is Jenny’s car’’ when the child says ‘’Mummy’s car’’. These expansions and extensions are all important as they give children examples of more advanced grammar. Children express a range of meanings in their two word speech as illustrated in [Table 3].

It is important to note that there is very considerable variation in the language progress of all children. In the study of 1803 typically developing children, [TODO: references 44] which provides the norms for the MacArthur Communicative Development Checklists (MCDI), average spoken vocabulary at 16 months was 44 words, while some children had only 2 or 3 words and others 120 words, and at 23 months the range was 50 to 550 words.

Table 3. Two word phrase categories.

(Adapted from Kumin [22, p.80])

Phrase category | Example |
Agent - Action | Mummy push; Baby push; (while pushing toy) |
Action - Object | Drink juice; Throw ball; Gimme ball |
Agent - Object | Daddy shoe (as he puts shoe on) |
Possessive | Mummy car; Sally doll |
Descriptive | Blue ball; Big truck |
Locative (place; where?) | In box; Slide down |
Temporal | Go now; Biscuit later |
Quantitative | Two ball; One cup |
Conjunctive (go together, and) | Cup plate; Shoe sock |
Existence | This bear; That biscuit |
Recurrence | More milk; More biscuit |
Non-existence (none here) | No bear; All gone juice |
Rejection (don’t want) | No milk; No want; No banana |
Denial (this isn’t) | No juice; No baby; No daddy |

Early grammar

A link between vocabulary size and grammar

When toddlers have spoken vocabularies of about 300 words (on average at 24 to 30 months), they begin to use some grammar. These will include the rules for expressing plurals, past and future tenses, possession and question forms.

The first grammatical rules that children learn are listed in [Table 4]. The ages in the table give the age range during which these are acquired by typically developing children. This table illustrates that the age at which this early grammar is learned by typically developing children varies widely. These first grammatical rules are mostly bound morphemes - that is grammatical markers attached to the word to change its meaning as in walk, walks, walking, walked. A morpheme is the smallest unit of meaning in spoken language.

Table 4. First grammatical rules that children master (Adapted from Harris [TODO: references 45]] p.12).
Age (months) | Progress |
19-28 | The present progressive tense on verbs (-ing), denoting an activity in progress - e.g., “He’s drawing.” |
27-30 | The preposition “on” - e.g., “Put it on the table.” |
27-30 | The preposition “in” - e.g., “It’s in the cupboard.” |
24-33 | The plural /s/ - e.g., “Dogs bark.” |
25-46 | The irregular past tense of verbs - e.g., “It broke”, “He ran away”, “I made it.” |
26-40 | The possessive /s/ - e.g., “Tom’s book.” |
27-39 | The uncontractable copula “be” form (that is, where the “be” form is used with an adjective, preposition or noun phrase and cannot be abbreviated) - e.g., “He is.” (In response to “Who’s there?”) |
28-46 | The articles “a” and “the” |
26-48 | Regular past tense forms - e.g., “Sally picked a flower.” |
26-46 | The third person singular /s/ for present tense verbs - e.g., “John rides the bike”; “He likes my dress.” |
28-50 | Irregular, third-person singular present tense; the verbs “have” and “do” become “has” and “does” for third-person sentence subjects - e.g., “He has two eyes”; “Mummy does the shopping.” |
29-48 | The uncontractable copula “be” form (that is, where the “be” occurs with a main verb and cannot be abbreviated) - e.g., “He is.” (In response to “Who’s coming to the party?”) |
29-49 | The contractible copula form (that is, where “be” occurs with an adjective, preposition or noun phrase and where abbreviation is possible) - e.g., “They’re inside”; “The boy’s dirty.” |
30-50 | The contractible auxiliary “be” form (that is, where “be” occurs with a main verb and abbreviation is possible) - e.g., “He’s laughing”; “Mummy’s cooking dinner.” |

Grammar - morphology and syntax

Grammatical markers and rules emerge in children’s speech in a generally predictable order. In this way, children slowly produce longer and more complex utterances until they talk in grammatically complete sentences like the adults in their community. Research suggests that children with a productive vocabulary of 300 words or less have very restricted grammatical abilities and that this vocabulary size is a ‘critical mass’ necessary for the productive grammar described in [Table 4], to begin to develop. [TODO: references 41], [TODO: references 46] This 300 word vocabulary needs to contain some nouns, verbs, adjectives, prepositions and some other grammatical words in order for the child to be able to construct sentences. (These categories of words and the order in which they are usually acquired are illustrated in the Vocabulary checklists in the accompanying practical DSii modules). Evidence that children are working out the rules of the language is provided by their tendency to use rules when they do not apply, such as saying ‘’goed’’ for ‘’went’’ or ‘’buyed’’ for ‘’bought’’.

Later grammar

Content and function words

Sentence structures or syntax (word order rules for questions or negatives etc) are steadily learned, and closed class grammar - sometimes called function words - is the last of the grammar to be mastered. Function words in English include the auxiliaries (is, are), articles (a, the), pronouns (she, him, they), prepositions (in, behind). These are the little joining words that may add to meaning in subtle ways or may just be conventions of the particular language being learned. It has been pointed out that function words are difficult to perceive as they tend not to be stressed when we speak. [TODO: references 11], [TODO: references 46] In contrast, verbs, nouns and adjectives are called content words - they carry the main meaning of the language.

The learning of grammar is influenced, like vocabulary learning, by the quality and quantity of talk with the child. [47-51] It is also influenced by being read to and by learning to read, since in books, sentences are written with complete grammar while in conversations the use of grammar is often abbreviated. It is thought that children learn how the language should ‘sound’ from constant exposure, so that the intonation and stress patterns help children to learn the correct grammar for their language. There is also a link between the rate of language learning and verbal short term or working memory development. [TODO: references 42], [TODO: references 90]

Is there a critical period for learning language?

A critical period for language?

An important question, particularly when considering how to help speech and language delayed children, is whether the brain has a timetable for language learning. The evidence suggests that the brain is most ready for speech and language learning between birth and 6 to 8 years, and the ability to fully master grammar and phonology may reduce after this time. It is important to stress that there is no evidence that speech and language skills cannot steadily progress into adult life, but if some control over grammar and phonology is not in place by six years, then the child may never get the fully sophisticated control over grammar and speech production that most of us take for granted.

Some observers believe that the development of grammar is triggered by the number of words that a child understands and that once the child has learned sufficient words, the brain begins to analyse the regularities in both grammar (e.g. plural ‘s’, possessive ‘s’, past tense ‘ed’) and in phonology (sound patterns, e.g. ‘s’,‘str’, ‘cr’, ‘ing’, ‘tion’). The view is that the brain is most ready to do this from 3 to 8 years. If the child does not have a large enough comprehension vocabulary by this age, then this analytical and computational system is not fully activated. Observers such as Locke [52,53] suggest that the parts of the brain that would be used for this specialist control over grammar and phonology will eventually be used for other purposes if grammar does not develop, explaining the evidence that the specialisation of different areas of the brain is often different in older children and adults when their development has been delayed or disrupted.

The reason for including this evidence is to underline to parents, therapists and teachers that early language intervention really is very important and it is important to expose children to listening to and saying grammatically correct sentences by five years of age if possible. This can be done with reading activities even for children who are not yet able to spontaneously use sentences. If Locke’s view of grammatical development is correct, and the evidence of the need for a 300 word vocabulary before grammar emerges suggests that it could be, then it is important to try to teach a language delayed child a 300 word vocabulary before they are 5 to 6 years old and preferably earlier.

Speech clarity and intelligibility

Speech skills - articulation, phonology, prosody, word finding and sentence planning

Speech is the term used here to refer to the child’s ability to produce intelligible words. In order to be able to speak clearly, the child has to be able to hear and accurately copy speech sounds (articulation) and word patterns (phonology). Once they wish to talk in sentences, they have to be able to produce a sequence of words. This requires word finding and sentence planning skills. They also have to be able to use the right intonations and stresses for the meaning of the sentence (prosody).

In typical development, the foundations for clear speech are being laid in the first year of life as infants babble. At first, babies produce a wide range of potential speech sounds in their babble but by 12 months they have tuned their babble to the language that they are hearing and now practice the sounds for that language in their babble. [TODO: references 54] In the second year of life they begin to attempt words, such as ‘’Dada’’. When they do this, parents respond, repeating back the word and providing a clear model for the speech pattern.

Research shows that the words that children will try to say is influenced by the sounds that they can say, [TODO: references 55], [TODO: references 56] so sound production skills (articulation and phonological development) are very important, and if delayed they can hold back productive vocabulary and grammar development, despite the child having good understanding and wanting to communicate. [TODO: references 121]

The ability to produce clear single words improves slowly and is followed by the ability to produce two words together. As this stage begins, the clarity of the individual words deteriorates a little with the demands of producing two words together, and then improves with practice.

Over several years, children’s speech clarity improves as they get increasing amounts of practice at talking. Some speech sounds, the blends such as ‘’st’‘,’‘cl’‘,’‘spr’‘,’‘cr’’, do not usually become clear until into the primary school years.

Steadily, children’s control over word and sentence production improves until they can generate clear sentences with complete word endings. Continuous speaking involves a set of processes including word finding, sentence formulation and planning as well as control over speech production. Some dysfluencies such as stutters may be related to phonological difficulties or to word finding and sentence formulation difficulties. [TODO: references 120]

Speech

Speech intelligibility refers to the speakers ability to get their message across - to be understood. Intelligibility is influenced by the listeners knowledge of the topic of the conversation and by other non-verbal and contextual cues in the situation as well as by speech clarity and sentence structure.

However, central to progress with speech clarity and intelligibility is practice and feedback. Speech production is essentially a motor skill, requiring motor planning and control, and like all other motor skills it will only improve with practice and the ability to monitor and learn from performance. The amount that a child talks each day will influence the amount of practice that they are getting.

The typical profile of speech and language development for children with Down syndrome

This section provides an overview of the main ways in which speech and language development for children with Down syndrome may be different from the typically developing child. It describes the delays that are usually seen and comments on some of the reasons. Activities to improve the progress of babies and children with Down syndrome at each stage from birth onwards are set out in the practical modules that accompanies this one.

It can be disheartening to read a list of the difficulties caused by having Down syndrome, particularly if you are a parent. However, the author believes that we will only be able to develop effective interventions if we understand the specific difficulties and design interventions to target them. In the past twenty years this approach has led to more effective interventions and to a greater appreciation of the strengths of the children.

Summary of the speech and language profile of individuals with Down syndrome

It is important to remember that no two children are alike and that there is just as much variation in the rates of progress and individuality of children with Down syndrome as there is among all children. This issue of variation is explored more fully towards the end of this section.

It is also important to remember that the communication skills of children with Down syndrome are a strength. They want to communicate and do so effectively in the early years and later, using gesture to compensate for their difficulties with spoken language. We all continue to use gesture and non-verbal communication skills throughout life but individuals with Down syndrome may make more use of these to compensate for their spoken language difficulties.

Early communication skills

Most babies with Down syndrome have good early non-verbal skills. They may make eye-contact, look and smile a little later than the typical infant. Once the babies begin to interact in this way, they like to communicate and enjoy smiling and babble games. This is a good foundation for being social and wanting to communicate, which continues through life for most children. [TODO: references 57] However, babies with Down syndrome are slower to move on to explore the physical world around them, both visually and by interacting with objects and toys. They are also slower at initiating and maintaining those joint attention sessions that are so important for language learning. [TODO: references 57]

They find it more difficult to maintain their attention on a toy or activity, and to keep switching attention from one toy or activity to another. Research with babies with Down syndrome has shown that it is very important to be responsive and to follow the babies’ lead and to talk about what they are already doing and attending to. For example, in one study, the mothers of typically developing children who kept initiating new activities for the child, had children with bigger vocabularies later. However, for the babies with Down syndrome in the study, this strategy did not help them. In this group, the mothers who followed the child’s lead and did not try to keep switching the child’s attention had children with larger vocabularies when they were older. [TODO: references 58]

Gesture

Most children with Down syndrome from about 18 months of age begin to imitate gestures, learning to wave and to point, just like other babies. They will go on to learn more gestures and to use gesture naturally as they get older. A number of research studies have highlighted that the use of intentional gestures to communicate is a particular strength for children with Down syndrome, and that they are sometimes even better at using gesture than typically developing children at the same level of cognitive ability. [59-61]

Many children with Down syndrome will be frustrated by delay and difficulty in producing clear words, but will be able to learn specific signs to use instead of words at this stage (about 2 to 4 years). This will help them to communicate when they do not yet have the words that they need to convey their message or when their speech is not understood. The benefits of teaching signs to aid both comprehension and production of words at this stage will be discussed later in this module.

Talking - vocabulary

Most children with Down syndrome are late in starting to talk. The average age for the first spoken word is about 18 months and for the first ten words, the average is about 27 months. Like other children, children with Down syndrome start using two words together when they have a productive vocabulary of about 50 different words. This occurs at around 37 months on average. [62-64]

After this, progress is usually steady but slow. The children begin to use three and four word sentences and to learn grammatical markers and different sentence structures.

However, most children with Down syndrome understand significantly more than they can say. Jon Miller and his colleagues, at the Waisman Centre, University of Wisconsin - Madison, USA, have carried out several comprehensive studies of early vocabulary development in children with Down syndrome. [16-18], [TODO: references 65], [TODO: references 66]

Firstly, they have identified three profiles of early language development among the children with Down syndrome. One third (34%) of the children had the language production skills that would be expected for children with their level of language comprehension and non-verbal mental abilities. However, the majority of children (64%) had language production skills that were poorer than expected for their language comprehension skills and non-verbal mental age measures. Only a small number of the children’s profiles (2%) showed language production behind language comprehension, with comprehension behind non-verbal mental age.

Secondly, their data shows that as the children grow older, the proportion that have language production skills lagging behind comprehension, increases to some 85% or more.

This research indicates that for many children with Down syndrome, even the production of first words lags behind their comprehension of words more than it does in typically developing children. This is a very frustrating situation for them and being able to sign at this stage will help them to communicate more effectively. If they can indicate their understanding by signing, this will encourage parents and carers to keep talking and including them in conversations.

Speech

Most children with Down syndrome find all aspects of speech production difficult. [TODO: references 7] While a number of studies indicate that babies with Down syndrome babble normally, they seem to struggle to say single words as early or as clearly as their typically developing peers.

They then find producing three and four words in a sequence difficult. Even words that they can say clearly as single words, become less clear when produced as part of a sentence. This was illustrated in a study of 9 children with Down syndrome over a four-year period by Hart. [TODO: references 67] She states ‘’the observers commented on the difficulty the children seemed to have in articulating more complex statements. The excessively rapid speech made most such extended statements largely unintelligible, so that listeners seemed regularly to ask the children to state their ideas more simply.’’ [67, p.219]

Hart concludes that ‘’All children in the study could have benefited during the prelinguistic period from therapy directed towards motor control of the tongue, mouth and vocal tract as well as exercises emphasising rhythm and pacing, awareness and control of starting and stopping gestures and sounds, and of gradually or abruptly increasing and decreasing their speed and volume’’. [67: pp 219-220]

There are almost certainly many complex reasons for these speech production difficulties, most of them needing further research. However, it is likely that many, if not most, children with Down syndrome discover that they are more likely to be understood if they use only two and three word utterances, thus increasing the chance of producing those words clearly enough for them to be recognised. [TODO: references 7], [TODO: references 19], [TODO: references 68]

These production difficulties will, in turn, influence input to the children and therefore their language learning opportunities. Communication needs a partner and it is likely that babies and children who are not producing sounds, words or sentences are spoken to and included in conversations much less frequently than those who are. This will be a significant risk from babyhood right through to adult life.

There is limited but consistent evidence that speech therapy can improve the children’s ability to speak clearly and that parents can effectively carry it out. This work is described in detail later. [69-71]

Grammar and sentence structures

! The links between vocabulary and grammar, showing the 50th, 10th and 90th percentiles for typically-developing children and for children with Down syndrome

Most children with Down syndrome struggle to learn the full grammar of their language. However, they do begin to join words together when they have a vocabulary of about 50 words, like other children, and they do show the same progress with grammar when their vocabulary reaches 300 words. [TODO: references 72] The scatterplot in [Figure 1] illustrates the way in which early grammar in the children’s speech was increasing as their total vocabulary size increased. The blue lines are percentile lines and they indicate the range of progress expected for typically developing children, as reported in Bates and Goodman. [TODO: references 46] The points on the scatterplot indicates the vocabulary size and grammar score obtained by each child with Down syndrome, as reported by their parents on the MacArthur Communicative Development Inventory (CDI). These 92 children with Down syndrome (percentiles indicated by the red lines) show essentially the same relationship between vocabulary size and grammar development as typically developing children.

Slow progress

The children with Down syndrome in this study are from 3 to 8 years of age. The blue lines represent progress for the typically developing children from 12 to 30 months of age. In other words, the development of the children with Down syndrome shows the normal link between vocabulary size and grammar, but they are acquiring vocabulary at a very slow rate. John Locke’s theory discussed earlier would suggest that this very slow vocabulary progress could be leading to the delayed grammatical development for children with Down syndrome. Most adults with Down syndrome have mastered only the simple grammar achieved before 5 years by most typically developing children. [TODO: references 73] Locke’s view would also suggest that phonological development - that is fully flexible control over the production of speech sounds in words - will also be inevitably delayed by the slow vocabulary acquisition.

Working memory

See also:

As children with Down syndrome get older their knowledge of vocabulary tends to be significantly ahead of their comprehension of grammar. In addition, as emphasised above, their production of grammar lags behind their comprehension of grammar. It has been suggested that this may be the result of difficulties with auditory processing and verbal short-term memory. [TODO: references 1], [TODO: references 8], [TODO: references 9], [TODO: references 12], [TODO: references 46] Children with Down syndrome have smaller short-term memory spans than other children of similar age and this will limit their ability to process sentences. These difficulties are explained more fully in the working memory module in this series.

Many teenagers are still using phrases made up of key words but without the function (joining) words or all the grammatical markers. For example, saying ‘he sit chair’ instead of ‘he is sitting on the chair’. This is referred to as ‘telegraphic’ speech. [TODO: references 74], [TODO: references 75]

No absolute ceiling

Intelligibility

Research points out that people with Down syndrome have difficulty with communicating clearly, and that people close to them learn to accommodate these difficulties:

In a survey of 937 families in America carried out by Libby Kumin and colleagues, 58% of the parents reported that their children with Down syndrome frequently had difficulty being understood, whereas only 5% reported that their children rarely or never had difficulties. [TODO: references 2]

A survey of 90 families in the UK in 1987 produced similar findings, with parents reporting that only 42% of teenagers could be understood by strangers when they were out in the community. However, when this study was repeated in 1999, 78% of teenagers who had been in mainstream education and 56% of those from special education could be understood when out in the community. Parents and teachers understood 90% of the teenagers in both studies. Intelligibility has been improved by inclusion in mainstream schools from infancy.

Robin Chapman and her colleagues, also of the Waisman Centre at the University of Wisconsin - Madison, have carried out the most extensive studies of the development of speech and language skills in older children. Their data shows that most teenagers with Down syndrome are still making slow but steady progress with productive grammar as they get older. That is, they have not reached a ‘ceiling’ and they continue to develop the use of longer and more grammatically complete sentences. [76-79] This is the case even when teenagers receive little or no speech and language therapy. Effective interventions into adult life would be likely to help most young people with Down syndrome improve their vocabulary, sentence structures and clarity when speaking. [TODO: references 9], [TODO: references 24]

This view is supported by the author’s intervention studies with teenagers, which provided activities targeted at production of grammar in sentences. This training over the period of one school year led to increases in conversational utterance length and grammatical complexity in the speech of the teenagers (see details of this study in the ’ Teaching grammar’ section). [TODO: references 74], [TODO: references 80]

Intelligibility

Joining in

The spoken language of many children and teenagers with Down syndrome is not always understood, especially by people not familiar with them. This is largely the result of poor speech clarity but it is probably also influenced by the telegraphic style as well. This will be very frustrating for children with Down syndrome and may lead to them being reluctant to initiate conversations as they often fail to make themselves understood. They will have more experience of successful conversations when they join in rather than start the conversation. If you join in, everyone already knows the topic of the conversation and therefore your contribution is more likely to be understood. This effect has been demonstrated in at least one research study with teenagers with Down syndrome. [TODO: references 68] Being able to join in with friends of the same age is particularly important in teenage years for developing friendships, being included in social and leisure activities and for independence.

Familiarity

Parents and teachers, who spend time with young people with Down syndrome regularly, may underestimate the communication difficulties that they will experience when trying to talk to people who have not known them long enough to become familiar with their speech.

Milestones and individual differences

[Table 5] provides a guide to expected rates of development in expressive language skills but the reader should remember that the majority of children with Down syndrome understand more advanced spoken language than they can produce when they talk. The reader should also note that, while the use of spoken language is delayed, the communicative uses of language listed in the ‘Interaction’ column are much the same as other children, at much the same age. In other words, children with Down syndrome want to express and share the same things as everyone else but they are restricted in the ways in which they can do so. The table gives a guide to average progress and there is considerable variation in rates of progress between individuals with Down syndrome. This variation is discussed further later in this section.

Table 5. Typical production milestones for children with Down syndrome
Age | Interaction | Vocabulary | Grammar | Speech |
0-12 months | Crying Eye-contact Smiling Listening/looking Vocalising - coos Turn taking | Understanding words | | Babble

Babble tuned to native language | | 12-24 months | Joint attention Gestures Conveying an increasing number of meanings in gestures and some words | Beginning to sign Beginning to say Words First 10 words | | Initial consonants and vowels developing as single sounds | | 24-36 months | Initiating conversations - pointing, requesting | First 30 words Comprehension ahead of production | Two words together | Words not very clear/intelligible | | 36-60 months | Repairing conversations when not understood - by trying again | First 100 words Rate of word learning increases At 5 years about 300 words | Two and three key words together Early grammar begins | Consonant, vowel and word production improve in accuracy | | 5-7 years | Learning to tell short narratives | Vocabulary learning continues to accelerate At 7 years about 400 words | ‘telegraphic’ sentences - keywords Increasingly correct short sentences | Consonant and vowel production continue to improve in accuracy | | 7-16 years | Taking part in longer topic related conversations Requesting clarifications using - What?, Where Telling stories Developing social use of language further - social small talk Taking account of listener’s knowledge knowing how to provide appropriate amounts of information for person or social situation Giving longer explanations or instructions Telling jokes Recounting experiences | More new words are learned each year Typical vocabulary size of older children and teenagers not known | Correct syntax being mastered slowly More difficult prepositions ‘above’, ‘below’, conjunctions ‘and’, ‘then’, ‘because’, comparatives - ‘longer than’ Grammar steadily extended to include passives in comprehension Many of these features are learned and used in reading and writing and then in speaking | Blends improve Speech becomes steadily more intelligible Speech rate and speech clarity continue to improve, influenced by reading |

Individual differences

Table 6. Age at which children reach 10 word and two word phrase stages (adapted from Oliver and Buckley [TODO: references 63])
| 10 word stage | 2 word phrases consolidate |
Number of children | 9 | 14 |
Average age (months) | 27.3 | 36.8 |
Range of ages (months) | 19 - 38 | 25 - 52 |

All research studies document the wide range of individual differences in progress with speech and language development among children with Down syndrome. The variation in rates of progress for children with Down syndrome is illustrated for individual children in the diary records kept by their parents during a study conducted by the author and colleagues. [TODO: references 63] In [Table 6] the age at which children reached 10 words in their spoken vocabulary and then the age at which they began to put two words together are illustrated. Some children were saying 10 words 19 months before others and some were putting 2 words together 2 years before others. These differences may be due to a number of factors, including level and frequency of hearing loss, extent of sound production (phonological) difficulties, degree of learning disability and the amount that the child is being talked to.

[Table 7] shows the ages for individual children reaching 10 spoken words and putting two words together when speaking. Interestingly, if adjusted, as in the last column for the 12 month delay in reaching 10 words, the children with Down syndrome only seem to take the same length of time as other children to go from first words to begin to put two words together in their speech. This may be because their understanding is in advance of their vocabulary production skills and they are wanting to express two word meanings in their communication, despite having only a small total vocabulary at this time.

Table 7. Individual profiles for early language production (adapted from Oliver and Buckley [TODO: references 63])
| Age at 10 word stage (months) | Age at 2 words together stage (months) | Age 2-word phrases adjusted\

to account for estimated 12 month
delay at 10-word stage (months) | | “A.L” | 23 | 31 | 19 | | “M.M” | 24 | | | | “F.M” | 23 | 30 | 18 | | “T.M” | 22 | 25 | 13 | | “E.C” | 31 | 39 | 27 | | “E.O” | 19 | | | | “M.T” | 38 | | | | “A.T” | 30 | 36 | 24 | | “V.W” | 36 | 41 | 29 | | “H.A” | | 34 | 22 | | “K.G” | | 33 | 21 | | “H.H” | | 33 | 21 | | “N.H” | | 49 | 37 | | “F.K” | | 40 | 28 | | “M.N” | | 42 | 30 | | “L.O” | | 31 | 19 | | “D.V” | | 52 | 40 |

Recently, the author and colleagues collected information on the language progress of 210 children with Down syndrome, using the MacArthur Communicative Development Inventories. [TODO: references 83] In [Table 8] the data for spoken words at each age group is given and in [Table 9] data for the words understood. The data in the columns reporting the ranges in both these tables again emphasise the widely differing rates of progress for different children with Down syndrome. For each age group the children understand more words than they can say.

Table 8. Total spoken words in the vocabularies of children with Down syndrome (adapted from Buckley, Pennanen and Archer, in preparation [TODO: references 115])
Age in months | Number of children in group | Mean spoken vocabulary size | Standard Deviation | Range of spoken vocabulary sizes |
15 - 23 | 12 | 10.7 | 12.7 | 0-38 |
24 - 35 | 17 | 28.1 | 34.9 | 0-125 |
36 - 47 | 44 | 116.7 | 102.9 | 1-399 |
48 - 59 | 26 | 247.8 | 144.9 | 22-481 |
60 - 71 | 32 | 271.6 | 180.4 | 8-586 |
72 - 83 | 39 | 330.4 | 174.8 | 0-640 |
84 - 95 | 32 | 390.5 | 160.6 | 80-615 |
96 - 107 | 8 | 434.2 | 184.5 | 166-604 |
Total | 210 | | | |

These data tables are included to give parents, teachers and therapists some guidelines as to the expected rates of language progress for children with Down syndrome. In the author’s experience it is useful to know whether a child is progressing faster or slower than might be expected for their age, in comparison with other children with Down syndrome, when planning teaching activities and advising parents.

Table 9. Total words understood by children with Down syndrome (adapted from Buckley, Pennanen and Archer, in preparation [TODO: references 115])
Age in months | Number of children in age group | Mean size of vocabulary | Standard Deviation | Range of vocabulary sizes |
15 - 23 | 12 | 124.8 | 77.1 | 34-254 |
24 - 35 | 17 | 166.9 | 101.0 | 25-309 |
36 - 47 | 43 | 233.4 | 93.0 | 69-424 |
48 -59 | 26 | 300.2 | 121.3 | 88-505 |
60 -71 | 31 | 334.4 | 148.6 | 80-586 |
72 - 83 | 38 | 360.8 | 153.6 | 62-642 |
84 - 95 | 32 | 416.8 | 147.7 | 90-628 |
96 - 107 | 7 | 471.9 | 162.4 | 215-604 |
Total | 206 | | | |

[Table 10] illustrates the progress with the early stages of grammar as measured for 84 children on the MacArthur Communicative Development Inventory. While there is steady improvement with age, there is considerable variation at each age level. Of the 210 children in the study, only 84 obtained a score on the grammar scale, the rest of the children had not yet reached this stage. The average production vocabulary in the grammar group was 416 words and the average production vocabulary in the no grammar group was 154 words, again supporting the view that the development of grammar requires a minimum vocabulary size.

Table 10. Mean, standard deviation and range of total complex phrases used (adapted from Buckley, Pennanen and Archer, in preparation [TODO: references 115])
Age in months | Number of children in age group | Mean number of complex phrases | Standard deviation | Range |
36 - 47 | 7 | 4.9 | 7.2 | 1-21 |
48 - 59 | 12 | 7.4 | 7.7 | 1-25 |
60 - 71 | 14 | 10.3 | 8.1 | 1-24 |
72 - 83 | 21 | 13.0 | 9.3 | 1-30 |
84 - 95 | 24 | 16.6 | 9.6 | 1-34 |
96 - 107 | 6 | 18.7 | 11.0 | 2-33 |
Total | 84 | | | |
Table 11. Mean grammatical complexity score (adapted from Buckley, Pennanen and Archer, in preparation [TODO: references 115])
Age | Male | Female |
3 | 1.5 | 6.2 |
4 | 9.2 | 5.7 |
5 | 7.5 | 11.4 |
6 | 9.0 | 18.4 |
7 | 10.7 | 17.0 |
8 | 15.8 | 33.0 |

[Table 11] illustrates that while there was no difference in overall vocabulary size for boys and girls in this study, the boys are slower than the girls at producing complex phrases. The researchers do not have any evidence that would explain this, but their clinical experience suggests that boys often have more severe speech production difficulties than girls and that this may be a partial explanation. More research is needed, which follows children longitudinally, to identify the causes of the wide differences in rates of progress between different children with Down syndrome of the same age and to explain any sex differences such as the one observed in this study.

Another illustration of the variation for emerging grammar is seen from the diary records kept of the progress of individual children. [TODO: references 62] [Table 12] illustrates the ages at which the children acquired the early bound morphemes explained in [Table 4].

[Table 12] indicates that if we take 12 months off the ages to allow for the 12 month delay in reaching production of 10 words, the children are mastering the morpheme rules in the same time from starting to talk as typically developing children.

Table 12. The comparison between the mean ages of acquisition of morpheme rules in children with Down syndrome and typically developing children (adapted from Rutter and Buckley, 1994 [TODO: references 62])
Progress | Mean age TD | Mean age DS | Mean age DS (minus 12 months) | Range TD | Range DS |
The present progressive tense on verbs (-ing), denoting an activity in progress - e.g., “He’s drawing.” | 28.7 | 40.8 | 28.8 | 21-35 | 30-52 |
The preposition “on” - e.g., “Put it on the table.” | 29.3 | 37.0 | 25.0 | 21-35 | 28-49 |
The preposition “in” - e.g., “It’s in the cupboard.” | 29.7 | 39.7 | 27.7 | 23-35 | 30-54 |
The plural /s/ - e.g., “Dogs bark.” | 30.3 | 41.2 | 29.2 | 25-34 | 28-50 |
The irregular past tense of verbs - e.g., “It broke”, “He ran away”, “I made it.” | 32.7 | 39.6 | 27.6 | 28-35 | 28-51 |
The possessive /s/ - e.g., “Tom’s book.” | 33.3 | 38.8 | 26.8 | 25-39 | 31-52 |
The uncontractable copula “be” form (that is, where the “be” form is used with an adjective, preposition or noun phrase and cannot be abbreviated) - e.g., “He is.” (In response to “Who’s there?”) | 33.3 | —– | —– | 27-38 | —– |
The articles “a” and “the” | 35.3 | 41.1 | 29.9 | 29-39 | 31-56 |
Regular past tense forms - e.g., “Sally picked a flower.” | 39.0 | 47.7 | 35.7 | 26-48 | 40-54 |
The third person singular /s/ for present tense verbs - e.g., “John rides the bike”; “He likes my dress.” | 39.0 | —– | —– | 30-45 | —– |
Irregular, third-person singular present tense; the verbs “have” and “do” become “has” and “does” for third-person sentence subjects - e.g., “He has two eyes”; “Mummy does the shopping.” | 40.0 | 44.0 | 32.0 | 31-50 | 44-44 |
The uncontractable copula “be” form (that is, where the “be” occurs with a main verb and cannot be abbreviated) - e.g., “He is.” (In response to “Who’s coming to the party?”) | 41.7 | —– | —– | 32-49 | —– |
The contractible copula form (that is, where “be” occurs with an adjective, preposition or noun phrase and where abbreviation is possible) - e.g., “They’re inside”; “The boy’s dirty.” | 42.7 | 51.5 | 39.5 | 33-50 | 42-79 |
The contractible auxiliary “be” form (that is, where “be” occurs with a main verb and abbreviation is possible) - e.g., “He’s laughing”; “Mummy’s cooking dinner.” | 43.3 | 44.7 | 32.7 | 34-50 | 44-45 |
Key: TD = Typically developing children\

DS = Children with Down syndrome |

The data reported in a recent American study of 168 children published by Libby Kumin and colleagues in Maryland, USA, illustrates the same wide range of individual rates of progress. This study documents the children’s progress with total productive vocabulary and this includes words that are signed as well as those spoken, which may account for the rather larger vocabulary sizes for each age than are reported in the English data. For example, while the average vocabulary in speech and sign was 168 at 3 years of age, the range was from 5 to 675 words for the children studied. Similarly, at 6 years, the average vocabulary was 468 words but the range for the children was from 57 to 652 words. [TODO: references 64]

By 5 years of age all the American children were using multi-word utterances, 27% sometimes and 73% often. At this age, 54% were using plurals sometimes, 23% often and 23% not at all. At 6 years of age, 60% were using the possessive ‘s’ often and 33% sometimes and 7% not at all.

See also:

The reader may observe that the children from the English studies ( [Table 12]) are reaching some of the early grammar milestones earlier than the American children. This may be because the English children were taking part in a study and their parents were observing and recording their development on a monthly basis. This may have made them more aware of their children’s progress and also more responsive to their language learning needs.

The practical modules for speech and language, and for reading, in this series encourage recording of children’s progress, as it is not only necessary for selecting intervention targets and recording progress, but it may also encourage and inform teachers and parents, and so influence progress.

Teenagers and adults

The speech and language skills of teenagers with Down syndrome

There is not as much detailed information available on the progress of speech and language skills during teenage and adult years as there is for children and the information that is available from standard tests shows that most young people with Down syndrome are still progressing steadily, but quite slowly in terms of fluent sentence production. [TODO: references 77], [TODO: references 78]

Teenagers continue to steadily learn vocabulary and their vocabulary knowledge is ahead of their grammar knowledge. In grammar, they have more difficulty with function words in comprehension and production than with the bound morphology. Their sentence lengths do slowly increase and they are more fluent when talking in narrative style (story or event reporting) than in conversation (often question and answer).

Their understanding of grammar is ahead of their ability to use it in sentences, and much of their difficulty may be due to their speech production difficulties. [TODO: references 74] Many teenagers and adults will communicate quite effectively but still in short keyword sentences, and they may be less inclined to start conversations than other teenagers. This may be because of the repeated experience of not being understood when starting a new topic. [TODO: references 10], [TODO: references 68]

In one teenage study in 1987, three out of 90 young people had no speech at all. For the 87 with speech, parents were asked about the length of utterance their teenagers used, as an estimate of productive grammar. While 70% of all the girls (at 11 to 17 years) and the older boys (14 to 17 years) regularly used sentences of five words or more, only half the younger boys did so. Conversely, 18% of the younger girls and 33% of the younger boys were limited to communicating in three word utterances or less, and 10% of the older teenagers were equally limited. [TODO: references 81]

In a further teenage study in 1999, the same authors were able to compare the progress of a new cohort of teenagers living in the same area as the 1987 group. [TODO: references 82], [TODO: references 84] In this second study, it was possible to compare the progress of teenagers who had been in mainstream schools with those who had been in special schools throughout their school career. All the teenagers (100%)in inclusive school placements were using sentences of 5 or more words and 83% were using complete grammar, whereas for those in special schools in 1999, 61% were using sentences of 5 or more words and 52% using grammatically complete sentences. This suggests that more stimulating environments and higher expectations are helping all children with Down syndrome, but that being in a normal language environment in an ordinary school is particularly beneficial.

The teenagers included in the mainstream schools were more than two years ahead in spoken language skills and more than 3 years ahead in literacy skills when compared with the teenagers in the special schools. There is no evidence that the two groups varied in ability at the start of their school careers.

See also:

Considering speech intelligibility rather than structure, in 1987, 42% of the teenagers could be understood by strangers, for example, if they were in a shop or restaurant and asking to purchase something. In 1999, 78% of the mainstreamed teenagers and 56% of the special school teenagers were reported to be understood by strangers in the community. About 90% of the teenagers in all the groups are understood by parents, teachers and those familiar with them.

These data do illustrate that the speech and language skills of most people with Down syndrome can improve if they are in more stimulating language environments. Most of these teenagers have not had significant amounts of speech and language therapy, so with targeted intervention as well as immersion in normal language environments, it is probable that much more progress could be made.

More severe speech and language difficulties

Some 10-15% of children with Down syndrome are significantly more impaired in speech and language skills and make significantly slower progress than most children with Down syndrome. Some of the children in this group have additional medical problems [TODO: references 81] and some have additional brain damage, so are slower in all areas of development and remain more dependent throughout their lives. Some of the group have more profound language learning difficulties, for reasons which are not clear, and some children are severely to profoundly deaf with losses greater than 60dB.

Autism

See also:

A few children with Down syndrome show autistic profiles and these children do not have good non-verbal skills such as eye-contact or smiling and they are not keen to communicate. [TODO: references 85], [TODO: references 86] In our experience, some children who appear ‘autistic’ in later childhood did have typical early non-verbal skills but did not go on to develop sign or speech and slowly became more withdrawn and ‘autistic’ over time. Some of these children are the ones with the more severe hearing losses.

In the author’s view, the dual diagnosis of autism and Down syndrome is being made too often and is only accurate in about 3-4% of children. Many of the children being labelled autistic have severe communication difficulties that could be improved and they do not have some underlying fundamental autistic type of social impairment. A greater number of children with Down syndrome do have some of the behaviours that are seen in ‘autistic spectrum’ disorders, at times during their development, as do many children with significant developmental delays but not Down syndrome. As their ability to communicate, to play and gain control over their daily lives improves, these ‘autistic like’ behaviours diminish in frequency.

Dyspraxia

Other children in the group that is more delayed in speech and language, are those with unusually severe speech production difficulties, which we would define as dyspraxic (neuromotor difficulties in producing the learned patterns of movement required for speech). Often these children do not have delayed comprehension early on, at the first word stage, but if they have very great difficulty making sounds and then words, this will have a significant impact on their experience of communicating and rate of language learning. Most of these children make slow but steady progress with speech during primary school years. It is important that the children with dyspraxic difficulties are identified as early as possible and that they receive more intensive and specific speech therapy than children with Down syndrome who do not have dyspraxia.

Explaining the profile of speech and language development

If we are going to try and improve the development of speech and language skills for children with Down syndrome, we need to identify as many of the specific reasons for their difficulties as possible. We have some pointers but by no means a complete picture of the causes let alone their interactive effects on the children’s progress. This section provides an overview of the current factors thought to contribute to the typical profile of speech and language difficulties for individuals with Down syndrome.

Learning or cognitive difficulties

Some of the reasons for the speech and language difficulties

All these difficulties can be targeted with appropriate and effective intervention strategies

Children with Down syndrome may be slower to understand the world around them and they may need more opportunities to link words to meaning than other children. If a typically developing child needs to hear the word ‘’cat’’ 5 or 6 times while looking at the cat, in order to make the link, the child with Down syndrome may need 10 or 12 times. No one knows exactly how many times either group of children need the experience to learn a word, but it is likely that the slower learning child needs more. Typically developing children pick up the meanings of words as they are used within sentences in everyday activities. Parents do not point to the cat and say ‘’cat’‘. They probably say things like’‘Look, there is the cat’‘, or’‘The cat is hungry’’. Children with Down syndrome may find learning word meanings from sentences more difficult, and will be helped by extra opportunities to learn from language teaching games in which words can be learned one at a time. This will be particularly helpful for early vocabulary, when it is mainly nouns and verbs that are being learned. Later, specific teaching of early grammar and sentence meanings may also help to accelerate learning.

Physical differences

The anatomical differences associated with Down syndrome, such as differences in skull shape, jaw, palate, dentition, tongue size relative to mouth and difficulties with motor skills development and fine movement control, will all contribute to the greater difficulties that children with Down syndrome have in developing clear speech. Therapy aimed at increasing oral-motor control from infancy will help articulation but there is no evidence that surgery for tongue reduction improves speech. [TODO: references 125]

Hearing loss

There are consistent reports highlighting the high risk of mild to moderate hearing loss for children with Down syndrome. [TODO: references 87] This is usually conductive loss due to ‘glue’ in the middle ear and therefore fluctuates over time. It affects up to 70% of children in their early years. [TODO: references 21] There is also an increased likelihood of sensori-neural loss (‘nerve deafness’) and this will have a permanent effect on hearing ability. In the author’s view, the significance of this high incidence of hearing loss on language learning is still underestimated. The long-term effects of glue ear are also not trivial. Michael Marcell and colleagues have demonstrated that as many as 40% of young adults may have permanent middle ear dysfunction and that these young people have poorer speech and language skills than those without the loss. Not only was their language knowledge less, they were also impaired on immediate speech recognition tasks. [TODO: references 88]

Auditory discrimination

In our practical experience, we see children who have difficulty in discriminating between similar sounding words, such as ‘dolly’ and ‘lolly’, ‘red’ and ‘bread’, ‘horse’ and ‘sauce’ even when their hearing is within normal limits. This will make it very difficult to learn to understand the words that they are hearing as toddlers and slow up vocabulary comprehension.

These examples are taken from one of our children’s case histories. The child wanted to use a single sign for each pair of words although he could demonstrate comprehension of the different meanings. We could conclude that he was only hearing ‘olly’, ‘ed’ and ‘orse’ for each of the pairs and he must have been very confused by the adult language system. To him it must have seemed as if we have one word for very different things! We suspect that this may be a common experience for children with Down syndrome. Imagine how much more difficult this would make language learning. (Children do have to cope with learning to understand ‘I’ and ‘eye’, ‘so’ and ‘sew’, ‘sail’ and ‘sale’ but the discrimination problems described will further increase a child’s learning difficulties).

Working memory

Working memory for individuals with Down syndrome

Working memory is the system that holds incoming verbal and visual information long enough for the brain to process it for meaning (not to be confused with long-term memory which is not generally impaired in persons with Down syndrome). The capacity of the verbal short-term memory part of this system can be estimated by finding out how many digits, said in random order at the rate of one per second, a child can repeat immediately in the same order (digit span). Typically, this digit span increases during childhood from about 3 digits at 4-5 years to 6-7 digits at 16 years. [TODO: references 89], [TODO: references 90]

Research has indicated that this system is linked to the listener’s efficiency of speech perception and speech production, and children usually get quicker at recognising and reproducing speech as they get older as a result of practice. Research has also shown that the efficiency of this verbal short-term memory system influences the speed at which children learn new vocabulary and learn to read. It is also thought to play a significant role in the processing and comprehension of speech and in organising speech production. [TODO: references 42], [TODO: references 90]

For children with Down syndrome, short-term memory span does not usually increase with age at a typical rate and most teenagers and adults only have spans of 2 to 4 digits. [TODO: references 74], [TODO: references 80], [91-94] The research on the significance of digit span in typically developing children suggests that this will delay vocabulary learning. It might be predicted to have an even bigger negative effect on the children’s ability to master grammar as this will usually require the ability to hold a whole phrase or sentence in short-term store in order to process it for meaning. There is some evidence that memory training can increase the short-term spans for children with Down syndrome and that improved span increases the rate at which grammar is learned. [TODO: references 126]

Learning language from listening is compromised

The difficulties in hearing, auditory discrimination and working memory can be summed up as indicating that learning language from listening, the way most babies do, will be difficult for children with Down syndrome.

Speech motor difficulties

The lack of clarity in the speech of most children with Down syndrome is likely to be due to a number of difficulties ranging from less effective operation of some or all of the brain mechanisms needed to plan and organise speech production to difficulties in moving the oral facial muscles and tongue with precision. [TODO: references 3], [TODO: references 7], [TODO: references 19], [TODO: references 95], [TODO: references 96]

The children have more difficulty establishing precise control over the muscles of the mouth, tongue and larynx, and this early control is influenced by sucking and chewing patterns and progress. Even if these speech mechanisms work effectively, the children may be having difficulty in hearing speech sounds and word patterns clearly enough to establish good templates to guide their production. They then have difficulty mastering speech sounds and using them in words.

Some observers suggest that it may take children with Down syndrome longer to find the words that they want and to organise sentences. [TODO: references 120] Working memory and information processing capacity may be relevant here and limiting the children’s progress.

The delays in producing first words and sentences severely reduces the amount of speech practice that children with Down syndrome experience, further adding to their delays in progress relative to typically developing children. These delays are also likely to reduce the amount of talk to and with children with Down syndrome.

Learning interactions and opportunities

The risk, then, is that children with Down syndrome will experience fewer language learning opportunities from infancy and throughout life, when it can be argued that they are likely to need more quality opportunities than typically developing children to learn language at an adequate pace. The evidence that babies with Down syndrome are not quite as good as typically developing babies at initiating joint attention sessions, maintaining attention on the task or switching attention between tasks suggests that they will need carers who are aware of these issues and who plan to compensate for them. Throughout childhood, everyone needs to be aware and try to compensate for the delayed and limited production of speech, recognising that this is likely to reduce the quality and quantity of opportunities to learn and to practice language and communication skills.

Summary

Building on strengths - increase daily communication experience

See also:

Children with Down syndrome are keen to be social and their interactive communication skills (ability to understand and participate in conversations) are good. This strength should be recognised and every effort made to enable them to communicate in all the settings that they are in at home and at school. They should be encouraged to continue to use gesture and sign to enable them to be effective and proactive communicators until their speech can be better understood. Everyone around them needs to be sensitive, to take time to listen and to include them. Language is learned and practised because children want to communicate.

Increasing the quantity and the quality of everyday communication experience for children and adults with Down syndrome is probably the single most important intervention and everyone can help to do this without special training, at home and at school. One implication of this is the importance of full inclusion in education and in community activities. Children need communication partners and to be immersed in normal conversational worlds. Special classes which put together children with severe language delays are not an appropriate daily environment for any child, and adults cannot compensate for the lack of communication between the children. Indeed their own communication to each other and to the children will be distorted by the children’s difficulties.

Targeting weaknesses - specific additional interventions

Comprehension and production of vocabulary needs to be taught through games and specific activities to help children acquire a 300 word production vocabulary before 5 years of age.

Articulation and phonology should be targets for intervention from the first year of life right through to adult life. Children only try a word if they can at least attempt some of the sounds in the word, therefore early work on phonology should speed up vocabulary learning. Since the emergence of grammar is linked with vocabulary size this should lead to earlier acquisition of grammar.

Grammar needs to be taught and reading may be the most effective way to support this, capitalising on the children’s strengths as visual learners and compensating for the small verbal memory span.

Is intervention for speech and language effective?

The Hanen programme

While the reader may agree that the proposals for intervention set out in the last section follow logically from the available evidence from research, the profile of language development of children with Down syndrome and the probable causes, is there actually any evidence that speech and language therapy or any other interventions will make a difference?

Unfortunately, the number of studies that have actually evaluated the effectiveness of interventions are few, despite the many papers describing the language difficulties of children with Down syndrome . A number of studies have reported on the progress of small numbers of children and usually report that language games and activities do result in faster progress but few of these studies have sufficient numbers of children or comparison groups to provide convincing evidence of effectiveness (see Spiker and Hopmann [TODO: references 97] for a recent review to 1997).

There have been some reported intervention studies, not covered in the 1997 review, in which the effects of the intervention have been adequately measured. These are discussed below in some detail as they illustrate many important principles for interventions. They also address issues often queried by speech and language therapists, such as the benefits of naturalistic, language interaction intervention compared to direct teaching approaches, and the benefits of direct work on phonology.

Teaching word production

Teaching single word production - Girolametto et al. 1998 [103]

The most recent research study that has evaluated the effectiveness of teaching specific target words to toddlers with Down syndrome is from the Canadian research team who developed the Hanen programme. [TODO: references 103] In 1998 they reported on a study that involved twelve children with Down syndrome and their mothers. The children ranged from 29 to 46 months of age and they communicated using at least 10 signs and words but did not use any combinations. Six children were assigned to the experimental group and six to a comparison group initially. The comparison group continued to receive regular speech and language therapy but received the targeted word programme later. The therapy programme consisted of the Hanen programme provided over a 13 week period, with 3 modifications. During the second parent training session, parents were given a list of 20 target words and they chose 10 that they thought their child would be motivated to learn. If the child used a word three times spontaneously in three different contexts (as determined by parent diaries) the word was replaced by another word from those remaining. Parents were taught to set up new routines that permitted modelling the target words many times. They were also trained to use signs as they spoke the words. Parents kept diary records of their children’s imitations or spontaneous productions of words.

Parents learned to use the target words in daily situations and to repeat the word at least 3 times during each interaction. For example, if the target word was ‘baby’, the parent was instructed to join in the child’s ongoing doll play and model the word by using labels or short comments (e.g. ‘baby’, ‘baby is sleeping’). The child was not required to imitate the word.

Choosing target words to teach

The 20 words were selected on the basis of the child’s MacArthur Communicative Development record, using 4 criteria. They were words that the child already understood but were not producing expressively, they were all words that typically developing children say by 24 months, all the target words started with a phoneme that was already in the child’s speech-sound repertoire and all words represented objects that could be used functionally or words that could be demonstrated using gestures (e.g. more, all gone).

The children in the experimental group learned significantly more of the targeted words than the children in the control group. The authors comment that larger studies are needed but the conclusion is that targeted vocabulary work is needed in addition to training parents to be effective and sensitive communicators.

Teaching two-word production

Teaching two word production - Clements-Baartman & Girolametto 1995 [104]

In a second study, members of the same team report on a study that compared interactive (modelling) versus didactic (direct instruction) therapy for teaching two-word utterances to two boys with Down syndrome over a six-week period. [TODO: references 104] Each child received experience of both training approaches using different target utterances in each approach. The boys were 4 year olds and they had a core spoken vocabulary of at least 50 words and showed evidence of readiness for learning two-word semantic (meaning) relationships by demonstrating evidence of at least one at the start of the intervention. The therapy consisted of hour long sessions provided by a therapist in the boys’ homes twice weekly over six weeks. This gave the boys 140 minutes of each treatment approach. Parents did not observe the sessions and were not informed of the targets for training during the research study so that they did not influence the outcomes.

In both therapy approaches, the therapist followed the child’s lead in play. Only toys representing the therapy targets were available to the child. In the interactive approach, the therapist modelled the target two-word utterance ten times per session as the child engaged in appropriate nonverbal play. In the direct instruction condition, the child was asked to imitate the researcher’s two-word utterance in response to a prompt e.g. say ‘in box’. If the child did not respond to a prompt, then a more specific request for imitation was made. A total of ten elicitations were attempted at each session.

In both conditions, if the child spontaneously produced a target two-word phrase the therapist responded to the communicative function of the production appropriately and then expanded on the utterance with a semantically related two-word target item.

Both boys showed significantly better learning from the direct instruction than the interactive therapy approaches - more efficient productivity and generalisation. They did learn from both approaches but the elicited imitation procedure was more effective than simply modelling. However, it is important to note that both approaches were conversationally embedded into theme-based activities that encourage joint attention. Teaching during joint action and attention episodes has been shown to maximise the child’s attention, facilitate comprehension of adult speech and associated learning. [TODO: references 127]

The boys learned in both therapy approaches and we suggest that the preferential effect of the didactic treatment may be related to the opportunity for them to practice target combinations and receive feedback on their attempts. They point out that as children with Down syndrome tend to experience difficulties with word finding and oral-motor speech skills, the didactic treatment embedded within naturalistic play may be an effective way to address the intrinsic language needs of these children.

Teaching grammar

Improving the speech and language skills of teenagers with Down syndrome - Buckley study 1993** [** [74]**]****, 1995 ** [80]

The only published intervention study that has attempted to improve comprehension and production of more advanced grammar and syntax is that of the author. [TODO: references 74], [TODO: references 80] Twelve teenagers took part in a year long language teaching programme. Twice each week they had individual sessions in which they practised production of syntactically complete sentences. Each sentence was imitated twice - the student repeating it after the teacher. The student then repeated the sentence on their own twice more. Twelve different examples of the same sentence structure were worked through at every session. All the sentences were supported by picture illustrations to act as prompts. For half of the new sentence structures learned during the year, the written sentence was under the picture as an additional support during the training trials, to allow the effect of reading as well as listening to be evaluated.

Training began with sentences that the student understood but could not say in full - that is, the student would use the key content words and leave out the function words -‘’He sit chair’‘, rather than ’He is sitting on the chair’. During the year, new structures were taught in comprehension as well as in production. All the training was audiotaped, transcribed and analysed to evaluate progress. At the start and end of the year, conversations were recorded with each teenager to see if any training benefits had transferred to their everyday spoken language. The teenagers enjoyed all the language training and were eager to come to the sessions.

In addition to the carefully organised repetitive practice of the sentence structures, examples of the structures being taught in this way were looked for in the student’s everyday experience and language books were made. These books were illustrated with photographs taken as the students acted out illustrations of the sentences. For example, for sentences using ‘above’ and ‘below’ as new concepts, one student sat on a table and one underneath the table. They wrote in the book under the photo ‘Julie is above Grant’, ‘Grant is below Julie’. They then changed places and we photographed ‘Grant is above Julie’ and ‘Julie is below Grant’. In the same manner, we took photographs to illustrate comparatives ‘Grant is taller than Shaun’, ‘Shaun is shorter than Grant’, ’ Grant is shorter than Stephen’……and passives ‘Shaun is pushing Grant’, ‘Grant is being pushed by Shaun’.

To add to the language books and further support generalisation of the training to everyday use we made conversation diaries to go between home and school. In these, the student decided what they would like to tell their family about their activities at school and this was written in the diary in the first person, to support narrative language (story telling or event reporting). For example, the student might write ‘I cooked sausage and mash today with Julie. We went to the shops first to buy the food’. At home the student might write ‘I went to the cinema with Grandad last night’ or ‘I watched TV with my brother last night’. In school, the diaries were read out each morning during a newstime slot in class. At home and at school, parents and teachers were asked to read with the student as necessary, as some could not read independently. Some students could write and read their own sentences but most had to copy the sentences and have support to read them correctly. Parents were requested to read with them and to help them to practise the sentences that they took home.

Working memory and speech (phonological and fluency) difficulties affected individual rates of progress

All the students benefited significantly from the training. This was demonstrated both in gains in the formal assessments of their comprehension and production and in the structure of their language in everyday conversations. Unexpectedly, the ‘least able’ students benefited the most from the reading support. They were the students with the poorest verbal short term memory spans and they simply could not repeat a six word sentence even when they had just heard it and had a picture prompt in front of them. However, they soon learned the printed words by repetition during the training sessions and used them to support correct practice. The students who could already read to a 7 or 8 year level, had longer digit spans of 3 or 4 digits (probably as a consequence of reading instruction) and could repeat the sentences correctly with or without the help of the printed version.

Gains in production over the year were affected by speech difficulties, those with the worst phonological or fluency problems made the least progress in production of sentences (though not in comprehension). The teenagers with the smallest digit spans at the start of the study also made slower progress in extending their productive sentence lengths. This could be because working memory capacity influences information processing ability as well as sentence planning and production.

Phonology

Phonological development - developmental errors

There have been three studies, two in Australia by Dodd and colleagues [TODO: references 69], [TODO: references 70] and one in Ireland by Ni Cholmain, [TODO: references 71] that aimed to improve the children’s phonology (speech sound production). All the studies involved the children’s parents as the main agents of change.

The first study initially involved 8 children aged 3 years 5 months to 5 years, one had no functional words and 3 made only delayed phonological errors. The other 4 were involved in the intervention programme as they had phonology that was inconsistent and typical of Down syndrome according to the authors. The parents met weekly for a comprehensive speech and language programme but with an emphasis on phonology. They chose to target whole word production, selecting 10 common and functionally important words for each child (family names, names of common foods and words like ‘more’, ‘no’, ‘again’). These 10 words were chosen in discussion with parents.

Some contrasting word pairs were given for voice/voiceless practice such as bee/pea, pat/bat, coat/goat, toe/dough or for omission of initial consonants egg/leg, egg/peg, eight/gate. Parents were told to accept an error if it was developmental (see side box) but to require consistent production. Words were to be elicited in games situations and parents made lotto games, played hiding games etc. High frequency words were chosen as far as possible in the hope that they would be used spontaneously and the child was then required to produce the word correctly. All the children made exceptional improvement in the percentage of consonants correct over 13 weeks (27% to 63%, 25% to 54%, 33% to 64%, 44% to 67%. Further the error patterns changed from deviant to normal (30% to 60%) and the gains were sustained 3 months later.

Targeting words, initially in isolation, then in sentence frames and spontaneous speech, allowed integrated teaching of phonology, vocabulary and syntax. Setting a small number of targets, especially as parents helped to choose them, provided feasible concrete goals. The choice of high frequency words - that is words that are in daily use - taught the child the power of having functional language. The intervention programme also involved the children’s preschools.

Targeting phonology produces rapid results - Dodd et al studies 1989 [69]], 1994 [70]

In the second of the Australian studies by Dodd and colleagues, [TODO: references 70] parents took part in the same 13 week training programme. The programme informed parents about all aspects of communication, language and speech and trained them in observation and listening skills as well as in responsive strategies to enable them to elicit word production during play with their children. This involved viewing video samples of each child and discussing their progress. There was much group support and discussion, and also individual counselling sessions. The second study again reported dramatic improvement in the children’s phonology at the end of just twelve weeks. Measures of the children’s spontaneous speech showed a mean increase of 30% in the percentage of consonants correct and a change of error type from inconsistent errors to developmental errors.

Dodd emphasises that phonology is inconsistent in the spontaneous speech of children with Down syndrome, not just delayed. As their production in imitation is better, this suggests a planning and motor control issue. She suggests that children with Down syndrome have a memory deficit for sequences of fine motor movement and that phonology programmes should therefore take account of the need to train motor memory. Prior experience of words seemed to make little difference as nonsense words were produced as well as real words.

Dodd and colleagues also stress the benefits of groups for intervention work with parents and children. They point out that groups provide a mutually supportive atmosphere in which parents are more responsive, and more likely to change attitudes and learn new procedures. They provide a wider range of learning and management problems for discussion, allowing advice to be given for handling future difficulties and sharing experiences. Groups can break down parent-professional barriers and professionals can become less rigid. Parents can become a source of ideas for management and develop their confidence and self-esteem. Groups are also cost effective.

In the second Australian study, the parent’s communication skills were rated before the study, 8 weeks into the programme and within 4 months of the end of the programme by videoing each of them with their child engaged in the same play activities on each occasion. The children’s progress was related to the parents’ skill in communicating. The nine children in this study were aged from two to six years of age and varied in their communication skills at the start. The three most verbal children (aged 4 years) showed improvement in phonology as reported in the first study. The three youngest children (two and three year olds) used few words at the start and half of these showed rapid gains in word use during the programme. Three other non-verbal children, aged 4 to 6 years, made little progress. Two of these children were described as having behaviour problems and parents reported that they were rarely able to gain their children’s co-operation in any activity. The third child had chronic illness that reduced the amount and scope of parental intervention.

Targeting phonology produces rapid results - Ni Cholmain study 1994 [71]

This study highlights the importance of recognising the variations in the development of children with Down syndrome. Two thirds of the children showed benefits in speech production skills and/or new word learning. Two children had poor attention skills and behaviour and the implication is that these needed to be improved before specific communication intervention would be effective. The third child was sick and therefore this was not a good time to ask parents to target communication work.

In the Irish study by Ni Cholmain, [TODO: references 71] six children aged from 4:1 to 5:6, were involved in the study. Their expressive language ages at the start of the study ranged from 1:2 to 2:9 years and the percentage of consonants that they could pronounce correctly ranged from 3 to 38%. All the children had reported hearing loss of more than 40dB at times in the past. They were in therapy in the speech and language service before the study, so baseline measures of rates of progress for the 3 months before the intervention were available. The programme focused specifically on phonology and each child’s listening and production activities were individually planned.

Listening

Parents were provided with portable sound amplifiers. These were used to provide the child with low-level amplification while listening to word lists containing the targeted phonemes for the child. The numbers of words on a list varied from 10 to 20 and 4 to 6 lists were worked on during any given period. The lists consisted of one list of words with a phoneme already in use contrastively and unaffected by the process in the child’s phonological system and 3 to 5 lists with the phonemes absent or affected by the process targeted. These lists were read to the child by a parent for 6 to 10 minutes every day. Each list was read twice and the list order followed. Parents were also encouraged to read a short story to the children at night as an additional listening routine. These were selected to include repetitions of words and phrase structures, but without reference to the current process or phoneme focus.

Production

Words for production practice were selected from those best approximated by the child in imitation activities using amplification during a clinic session. Five to 10 words were given containing one or more examples of the target process. These words were practised using amplification following the listening session. Parents were also encouraged to focus on the words in activities such as shop games and picture lottos. They were also encouraged to use clarification requests, indicating uncertainty, regarding objects named or requested during games and everyday routines.

Sound practise

Sound cards or books were provided for the children. These contained picture symbols both for phonemes being targeted and those already in the child’s system. They were used to encourage the children to think about speech sounds as sounds, and provided opportunities for listening and production practice in play.

The programme was applied on a cyclical basis with input periods of 4 to 6 weeks followed by a break of 4 to 10 weeks. During the input period the children were seen by their therapist on a weekly or fortnightly basis for identification of processes to be targeted, provision of word lists for listening, and production practise and reassessment. Parents practised work for 20 minutes daily when possible.

All the children in the study showed change in their phonological systems within the first two weeks, which Ni Cholmain describes as reflecting the beginning of a reorganisation of the child’s system. Not all new phonemes or process changes were fully achieved in the time period of the study but they did indicate movement towards mastery. The percentage of consonants correct changed from 3 to 38% before intervention to 19-88% correct. The author describes that the progress of the phonological changes seen was as would be predicted from normal developmental progress. The processes eliminated first were those dropped earliest in typical development i.e. initial and final consonant deletion, nasalisation and stopping.

Ni Cholmain reports that the programme appeared to have encouraged the children to recognise that a phonological system existed and that their own systems required reorganisation. The increased intelligibility that resulted appeared to liberate the children’s syntax development as reflected by a move into early grammar.

Multi-sensory approaches to support learning from listening

Signing

The benefits of using signs as a bridge to talking

The available evidence suggests that parents should be encouraged to learn to use sign to support the development of spoken language with their baby from 7/8 months of age. Research studies show that children with Down syndrome do not learn words easily from speech input on its own [TODO: references 105], and that those who have been in sign supported therapy programmes have bigger spoken vocabularies at 5 years. [TODO: references 16], [TODO: references 20], [TODO: references 64]

Practitioners have advocated the use of augmentative signing with babies with Down syndrome since the early 1980s [TODO: references 106], [TODO: references 107] and evidence for its effectiveness has slowly accumulated. It can help in a number of ways. If parents sign as they speak, they make sure the baby is looking, the sign holds the baby’s attention and it gives an added clue to the meaning of the words. Parents are also likely to stress the words they are signing. In other words, signing may help to structure more effective language learning situations.

For infants, signing can increase their productive vocabularies as they can usually sign words before being able to say them. Signing will reduce frustration and increase communication opportunities. They know what they want to say but cannot yet produce the words. At this stage, signing helps to maintain effective communication, and is likely therefore to increase the rate of language learning until speech emerges, as it is hard to keep talking to a non-talking child.

However, it is essential to keep up activities to encourage sound and speech production alongside the use of signing, if children are to move into using spoken words as early as possible. In the author’s experience, most children are able to drop the use of sign slowly from around four to five years of age, though they should not be discouraged from using sign at any age as a repair strategy when their speech is not understood.

The possible ways in which signing may assist speech and language skills in people with Down syndrome warrants more sophisticated analysis than we have available to date since one study illustrated that the speech clarity of adults with Down syndrome improved when they signed as they spoke. [TODO: references 108] Individual case examples from parents and practitioners indicate that signing often helps the child with Down syndrome to find the word they want and to speak more clearly. Signs for sounds have helped production of initial and end sounds in words and signs for grammatical markers can help to teach grammar.

By school age, reading activities can increasingly take over as the support system for language learning and spoken language should be encouraged as the main means of everyday communication.

Teaching reading to teach grammar

The benefits of teaching reading to teach talking

Current evidence suggests that teaching children with Down syndrome a sight vocabulary should be a routine part of speech and language therapy and a priority in all early intervention and education programmes. [TODO: references 24]

Learning to read will help vocabulary learning and it will particularly support grammar and sentence learning. [TODO: references 40], [TODO: references 80], [109-113] Three to four years of age is the optimal time to start for the majority of children, 2 years for some, later for others. Once a child has a comprehension vocabulary of about 40 to 50 words and can play picture lotto games, that is, match, select and name pictures in speech or sign, reading should be introduced. [TODO: references 114] Production of multi-word utterances and sentences with correct grammar can be greatly assisted by reading sentences.

Reading also supports speech practice and can improve articulation. The sounds and word patterns become visual clues to how to say the sound or word. Once letter sounds are known, letters can be used to support practice. Teaching a sight vocabulary, choosing words with different initial sounds, sound patterns and number of syllables, will help to build speech practice. Children with Down syndrome speak more clearly, with more accurate phonology, when reading, as do other children. This is probably partially due to the fact they do not have to plan the sentences that they read, so freeing up more information processing capacity for controlling speech production.

In the author’s view, early reading activities may be one of the most effective interventions to develop the speech and language skills of children with Down syndrome. Children who have been taught to read from 2 to 3 years of age, as part of a language teaching programme are frequently among the most advanced children with Down syndrome in speech, language, and cognitive skills. It is possible that at this age the brain is most receptive to learning a first language visually, or simply that the reading is a very effective way of structuring the teaching of words and sentences, and supporting spoken practice. Children who engage in 20 minutes a day of reading practice, even if it is in imitation, are getting consistent practice of speaking in grammatically correct sentences long before they are able to generate such sentences spontaneously in daily communication.

Some research indicates that learning to read during the school years accelerates both language and memory development for children with Down syndrome in the way that would be predicted from research with typically developing children. [TODO: references 124] Children with Down syndrome included in mainstream classes are likely to achieve higher levels of literacy than those in special schools - by more than 3 years progress - and will be ahead by more than 2 years in spoken language skills. The two gains are probably linked as the included children read and write everyday as they work in school, even if they cannot do so independently, as they have classroom assistants.

The importance of reading and writing activities, linked to the children’s level of language knowledge, the curriculum and social needs, throughout primary and secondary school, cannot be over emphasised. The benefits may be greatest for the children who become independent readers, but the benefits for the children who need considerable support for reading and writing are also likely to be significant.

Conclusion

The evidence from available research does suggest that: -

Improving the quality, quantity and sensitivity of the talk to children with Down syndrome does help - this would be the kind of change encouraged by a scheme such as the Hanen programme [TODO: references 128] - and suggested by the review of influences on the language development of all children at the start of this module. [100-102]

This type of language experience approach is not sufficient on its own but needs to be accompanied by teaching specific vocabulary and sentences, using techniques which encourage the child to imitate production. [TODO: references 103], [TODO: references 104]

Targeted work does improve phonology from as early as 3 years for speech sound and word production and as early as the first year for listening, sound discrimination and sound copying practice. [69-71]

Signing is an important aid to accelerating early language learning but the emphasis should always be on speaking and sound and word production work are important at the same time. Reading is also of fundamental importance to developing effective speech and language skills - both reading to children with Down syndrome and teaching them to read.

This module has shown that we know a great deal about how children learn their native language and become competent talkers. It also illustrates that we know a great deal about the language learning difficulties of children, adolescents and adults with Down syndrome and how to help them to overcome them.

The important principles, which should guide intervention and daily talk with children and adults, have been set out. The practical modules provide detailed plans to follow, including assessment lists so that the gestures, sounds, words and grammar a child is using can be assessed in order to start activities that are appropriate for each individual child. Ideally each child should have the support of a speech and language therapist but as this is not always available, the practical guidance should allow a parent, teacher or classroom assistant to effectively improve the spoken language skills of their child without other help if necessary.

Acknowledgements

The author would like to thank all the children, families and colleagues that she has worked with over the past 30 years in intervention services for their contribution to her understanding of the issues discussed in this module.

The author would also like to acknowledge the contribution of all of the staff and students in the Psychology Department at the University of Portsmouth, and at Down Syndrome Education International who have been involved in the research studies.

This module has been improved and influenced by discussions with Patricia Le Prevost, Ben Sacks, Gillian Bird, and the members of the UK Education Consortium, all of whom also read and commented on drafts. However, any errors and statements of opinion remain the responsibility of the author.

Terminology

The term ‘learning difficulty’ is used throughout this module as it is the term currently in common use in the United Kingdom. The terms ‘mental retardation’, ‘intellectual impairment’, and ‘developmental disability’ are equivalent terms, used in other parts of the world.

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