Revision- Child Language Acquisition

Theories: 

Imitation & reinforcement theory (Skinner, 1957)
Skinner was a proponent of the theory that children acquire language by imitating the way others speak. When the child is successful at producing words it is praised. This approval motivates the child to repeat the action thus learning words.
This theory has now been largely discredited. The task of acquiring language is such a vast one – children acquire tens of thousands of words and complex rules of grammar and syntax within a very short space of time. 
Further flaws in this theory are revealed if we consider the mistakes children make in their grammar usage. They clearly do not imitate statements such as “I cleaning my tooths”. This is not a sentence formation which would have been praised by an adult.

Innateness theory (Chomsky, 1965)
Noam Chomsky argued against Skinner's theory. He reasoned that children have an innate ability to acquire language through what he called a ‘language acquisition device' (LAD).
Chomsky claimed that all languages have a different surfacestructure - French and English sound different from each other through their differing intonations and stresses. However, he felt that all languages share the same deep grammar structure, or linguistic universals - subject–verb-object. His theory suggests we are pre-programmed with this deep structure. Chomsky's theory explains how children can understand sentences they've never heard before.
Critics such as Bard and Sachs (1977) argue that children don't learn to speak automatically. They need to communicate and interact with others – innateness alone is not enough.

Cognition theory (Piaget, 1966)

The cognition theory links stages in language acquisitionwith stages of cognitive development. Piaget observes that children initially view themselves as the centre of the universe believing that objects exist only in relation to themselves. At around 18 months children begin to realise that objects have an existence that is nothing to do with them. A big growth in vocabulary occurs at this time and proponents of the cognition theory suggest that these events are linked - children are compelled to find names for things they now know exist. Piaget's theory shows a relationship between language and thought – though the theory only seems to stand up for the first 18 months of a child's life. Studies show that some children whose mental development is retarded can speak fluently. Here it seems that word order, meaning and grammar have not been subject to the child's general cognitive development.

Lenneberg's (1967)

Cut off age: As well as theories on how children acquire language, there are theories about when. Eric Lenneberg's (1967)theory suggests that there is a critical period in a child's life during which they are able to acquire language. What is the duration of this period? What evidence is there for and against it?

Lenneberg's theory claims that language acquisition is linked to maturation. He proposes that the human brain is designed to acquire language at a certain time.

Lenneberg suggested that there is a cut-off age of around 12 or 13 years and that once this period has passed language learning slowed down or in effect was no longer possible.

The Science Behind It: the brain begins to grow at around 18 months old. It has acquired grammar and phonology by about four years of age and it is widely accepted that an ability to acquire language probably extends this learning period up to the middle of the second decade.

After this point, it is said that there is a decline in the neural plasticity of this area of the brain, severely impairing language acquisition ability.

Assessing lennenbergs story: Genie’s Story: Unfortunately, there have been occasions to test Lenneberg's theory. Studies highlight the plight of ‘Genie', a 13 year old American girl raised in appallingly deprived circumstances. Locked away from the world, deprived of language and forbidden to speak, she was denied human interaction. When she was discovered she did not have language as we know it – just ‘grunting' sounds. Despite many and varied learning programmes, Genie neverspoke in a fluent manner.

It appears that Genie was rescued too late to acquire language within the critical period.

Assessing lennenbergs story: victors Story: Victor, often referred to as a feral child was discovered at 12 years of age. Initially, he was mute and again despite extensive treatment and a loving carer he never learned to speak properly. There are criticisms of Lenneberg's theory: Some ask the question: Were Genie and Victor intellectually damaged from birth and incapable of learning how to speak? Others ask: Were the speech therapists and specialists' methods inadequate in helping Genie and Victor? Would they have fared better in the care of others? Has lennenbergs story been accepted  It has been widely accepted that there is some truth in Lenneberg's theory. The immense language learning ability, which accompanies us through our early years, does seem to be shut down by some kind of genetic programming around the time of puberty. Genie and Victor's cases would have also supported a theory by another well known psychologist - Vygotsky. Vygotsky (1978), argued that a child is only able to acquire language when he is interacting with people in his environment and, in particular, in co-operation with his peers. Obviously, neither Genie nor Victor had the opportunity to do this Model Answers From A Transcript: “Look at my picture Mummy. I drawed it at playgroup. There was a pretty girl called Sadie and she got a red hood and then the nasty wolf killed her and she got dead and then and then the mens made her better with a kiss.” Model Answers: At three years plus Sam is using more complex language and ideas in the story on the tape. It is full of information and he is using longer and longer utterances. He is able to use verbs but the tense is still problematic (‘I drawed' instead of ‘I drew') where the endings are irregular. The overused rule at this stage is that children tend to assume that all past tenses end in –ed. Adjectives are used (pretty, red) and he uses conjunctions to allow additional information into the story but they are limited as shown by he repeated use of ‘and' and ‘and then'. There is still some difficulty with irregular pluralisation (mens). ·        Over-extension Children over-extend word meanings. This means that they will extend the meaning of one category of item more broadly than it should be. An example of this might be calling all round fruits ‘apples' when they are perhaps oranges, kiwis or cherries. Under-extensionChildren under-extend word meanings. This means that they will not accept that there are more examples of a category of item than the particular one that is familiar to them. So, for example, ‘dog' is used for the family pet but does not apply to any other dog, thus narrowing the word's meaning