Learning to talk

[TODO]

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.

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 beginning to learn the sounds of their language from the first weeks of life. They need to hear (perceive) the speech sounds, be able to distinguish them from one another, store them and then learn to make the sounds themselves. They start this process of learning to hear the speech sounds from the first month of life. After a few weeks, they begin to coo, to produce vowel like sounds and then some consonant sounds such as ‘b’ and ‘d’. They then begin to babble, that is, join sounds to say ‘baba’, dada’. The babble sounds they produce predict the first words they will say. Ref Stoel-Gammon. The consonant sounds they produce at 11 months of age influence the development of their verbal short term memory. TODO: Keren-Portnoy ref.

Babies are listening and practising sounds as they babble and they are also 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. Their progress with babble also influences how often they are spoken to as it is natural to respond when the baby babbles.

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

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

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 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.

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^[1]).

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.^[2]

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])

Early 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^[3] p.12).

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.^[4],^[5] 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. (TODO: Review) (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

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],^[5] 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.^[6,7]

Is there a critical period for learning 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 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 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.