Home > THEORIES OF LANGUAGE ACQUISITION
Over the last fifty years,
several theories have been put forward to explain the process by which
children learn to understand and speak a language. They can be
summarised as follows:
Theory |
Central Idea |
Individual with theory |
Behaviourist | Children imitate adults. Their correct utterances are reinforced when they get what they want or are praised. | Skinner |
Innateness | A child's brain contains special language-learning mechanisms at birth. | Chomsky |
Cognitive | Language is just one aspect of a child's overall intellectual development. | Piaget |
Interaction | This theory emphasises the interaction between children and their care-givers. | Bruner |
We shall consider each of these in turn. Before we do, it is important to recognise that they should not be seen simply as conflicting theories, replacing each other in a sequence. Although Behaviourism is now seen as offering only a very limited explanation, each theory has added to our overall understanding, placing emphasis on different aspects of the process.
The behaviourist psychologists
developed their theories while carrying out a series of experiments
on animals. They observed that rats or birds, for example, could
be taught to perform various tasks by encouraging habit-forming.
Researchers rewarded desirable behaviour. This was known as
positive reinforcement. Undesirable behaviour was punished
or simply not rewarded - negative reinforcement.
The behaviourist B. F. Skinner
then proposed this theory as an explanation for language acquisition
in humans. In Verbal Behaviour (1957), he stated:
"The basic processes and relations which give verbal behaviour its special characteristics are now fairly well understood. Much of the experimental work responsible for this advance has been carried out on other species, but the results have proved to be surprisingly free of species restrictions. Recent work has shown that the methods can be extended to human behaviour without serious modifications."
(cited in Lowe and Graham,
1998, p68)
Skinner suggested that a child imitates the language of its parents or carers. Successful attempts are rewarded because an adult who recognises a word spoken by a child will praise the child and/or give it what it is asking for. Successful utterances are therefore reinforced while unsuccessful ones are forgotten.
While there must be some truth
in Skinner's explanation, there are many objections to it.
Child: Nobody don't like me
Mother: No, say, "Nobody likes me."
Child: Nobody don't like me.
(Eight repetitions of this dialogue)
Mother: No, now listen carefully: say, "Nobody likes me."
Child: Oh! Nobody don't likes me.
(McNeil
in The Genesis of Language, 1966)
Noam Chomsky published a criticism
of the behaviourist theory in 1957. In addition to some of the
arguments listed above, he focused particularly on the impoverished
language input children receive. Adults do not typically speak
in grammatically complete sentences. In addition, what the child
hears is only a small sample of language.
Chomsky concluded that children
must have an inborn faculty for language acquisition. According
to this theory, the process is biologically determined - the
human species has evolved a brain whose neural circuits contain linguistic
information at birth. The child's natural predisposition to learn
language is triggered by hearing speech and the child's brain is able
to interpret what s/he hears according to the underlying principles
or structures it already contains. This natural faculty has become
known as the Language Acquisition Device (LAD).
Chomsky did not suggest that an English child is born knowing anything
specific about English, of course. He stated that all human languages
share common principles. (For example, they all have words for
things and actions - nouns and verbs.) It is the child's task
to establish how the specific language s/he hears expresses these underlying
principles.
For example, the LAD already
contains the concept of verb tense. By listening to such forms
as "worked", "played" and "patted", the
child will form the hypothesis that the past tense of verbs is formed
by adding the sound /d/, /t/ or /id/ to the base form. This, in turn,
will lead to the "virtuous errors" mentioned above.
It hardly needs saying that the process is unconscious. Chomsky
does not envisage the small child lying in its cot working out grammatical
rules consciously!
Chomsky's ground-breaking theory remains at the centre of the debate about language acquisition. However, it has been modified, both by Chomsky himself and by others. Chomsky's original position was that the LAD contained specific knowledge about language. Dan Isaac Slobin has proposed that it may be more like a mechanism for working out the rules of language:
"It seems to me that the child is born not with a set of linguistic categories but with some sort of process mechanism - a set of procedures and inference rules, if you will - that he uses to process linguistic data. These mechanisms are such that, applying them to the input data, the child ends up with something which is a member of the class of human languages. The linguistic universals, then, are the result of an innate cognitive competence rather than the content of such a competence."
(cited in Russell, 2001)
Evidence to support the innateness theory
Work in several areas of language study has provided support for the idea of an innate language faculty. Three types of evidence are offered here:
(Note: some of this
section is derived from the BBC television documentary The Mind Machine.)
Limitations of Chomsky's theory
Chomsky's work on language
was theoretical. He was interested in grammar and much of his work consists
of complex explanations of grammatical rules. He did not study
real children. The theory relies on children being exposed to
language but takes no account of the interaction between children and
their carers. Nor does it recognise the reasons why a child might
want to speak, the functions of language.
In 1977, Bard and Sachs published a study of a child known as Jim, the hearing son of deaf parents. Jim's parents wanted their son to learn speech rather than the sign language they used between themselves. He watched a lot of television and listened to the radio, therefore receiving frequent language input. However, his progress was limited until a speech therapist was enlisted to work with him. Simply being exposed to language was not enough. Without the associated interaction, it meant little to him.
Subsequent theories have placed greater emphasis on the ways in which real children develop language to fulfil their needs and interact with their environment, including other people.
The Swiss psychologist Jean Piaget placed acquisition of language within the context of a child's mental or cognitive development. He argued that a child has to understand a concept before s/he can acquire the particular language form which expresses that concept.
A good example of this is seriation.
There will be a point in a child's intellectual development when s/he
can compare objects with respect to size. This means that if you
gave the child a number of sticks, s/he could arrange them in order
of size. Piaget suggested that a child who had not yet reached
this stage would not be able to learn and use comparative adjectives
like "bigger" or "smaller".
Object permanence is another phenomenon often cited in relation to the cognitive theory. During the first year of life, children seem unaware of the existence of objects they cannot see. An object which moves out of sight ceases to exist. By the time they reach the age of 18 months, children have realised that objects have an existence independently of their perception. The cognitive theory draws attention to the large increase in children's vocabulary at around this age, suggesting a link between object permanence and the learning of labels for objects.
During the first year to 18 months, connections of the type explained above are possible to trace but, as a child continues to develop, so it becomes harder to find clear links between language and intellect. Some studies have focused on children who have learned to speak fluently despite abnormal mental development. Syntax in particular does not appear to rely on general intellectual growth.
In contrast to the work of Chomsky, more recent theorists have stressed the importance of the language input children receive from their care-givers. Language exists for the purpose of communication and can only be learned in the context of interaction with people who want to communicate with you. Interactionists such as Jerome Bruner suggest that the language behaviour of adults when talking to children (known by several names by most easily referred to as child-directed speech or CDS) is specially adapted to support the acquisition process. This support is often described to as scaffolding for the child's language learning. Bruner also coined the term Language Acquisition Support System or LASS in response to Chomsky's LAD. Colwyn Trevarthen studied the interaction between parents and babies who were too young to speak. He concluded that the turn-taking structure of conversation is developed through games and non-verbal communication long before actual words are uttered.
These theories serve as a useful
corrective to Chomsky's early position and it seems likely that a child
will learn more quickly with frequent interaction. However, it
has already been noted that children in all cultures pass through the
same stages in acquiring language. We have also seen that there
are cultures in which adults do not adopt special ways of talking to
children, so CDS may be useful but seems not to be essential.
As stated earlier, the various theories should not be seen simply as alternatives. Rather, each of them offers a partial explanation of the process.
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