The Acquisition of Language
The Acquisition of Language
By Rajat Passy
Word Count: 1830
Theories of language acquisition should clearly be evaluated in terms of how adequately they predict and explain the behaviour that is observed. Despite the fact that a detailed description of language acquisition has not yet been obtained (Lucy, 1992), a lengthy and controversial discussion has taken place in the literature concerning theoretical explanations of children's language acquisition and development. In this essay, only a brief summary of the three major models will be put forward, which will allow us to review some of the principal questions still to be empirically answered: why do children acquire language; how do they go about acquiring it; and, what is it that they acquire?
The systematic study of language acquisition began in the late 1950's, around the time when cognitive science was in its developmental stage. Chomsky's (1959) 'Review of Skinner's Verbal Behaviour' ruthlessly attacked the prevailing consensus - the mind consists of sensorimotor abilities with a few general laws of learning which control gradual changes in the organisms behaviour. Therefore, language must be learned and since verbal behaviour is the only manifestation of thought that can be externally observed (Skinner, 1986), thinking must only be a form of internal verbal behaviour (Pinker, 2000). Chomsky, on the other hand claimed that children learn languages based on highly subtle and abstract principles, yet they acquire these principles without any explicit instruction. Hence, language acquisition depends on an innate, species-specific unit that is separate from general intelligence (Chomsky, 1957).
Besides these two opposing theses, there exists another model of language development: the evolutionary/biological model. The shape of the human vocal tract is clear evidence of evolution demanding speech. The larynx is situated low in the throat and the vocal tract has a sharp bend that creates resonant cavities (the mouth and the pharynx), both of which help produce vowel sounds. But these have come with a life threatening sacrifice in efficiency of breathing, swallowing and chewing (Lieberman, 1984 cited in Pinker, 2000). Choking has been a common cause of accidental death until the invention of the Heimlich manoeuvre (Pinker, 2000). The evolutionary selective advantages for language must have been significantly large to prevail over such basic needs such as eating and swallowing efficiently. One is made to wonder that if language is truly derived from Darwinian natural selection, then finding it in our closest relative, i.e. the chimpanzee, must not be difficult. However, in several famous but controversial studies, chimpanzees have been taught to use basic hand-signs and to understand some spoken commands (Gardner & Gardner, 1969; Premack et al., 1983, 1991 cited in Pinker, 2000). These have been successful, but only to a limited extent. This lack of homology does not cast any uncertainty on the Darwinian account of language evolution. Humans did not evolve from chimpanzees; they both had common ancestors perhaps 6-7 million years ago which leaves 300,000 generations in which language could have evolved in humans (Stein, 2003).
The aforementioned evolutionary model is a relatively novel concept. The following section will return to the more classical and empirically evidenced theories discussed earlier, beginning with the behaviourist view. The behaviourists argue that language development takes place even before birth and is part of the general learning process of a child. They only study behaviour that can be measured or observed, hence it is synonymous with the 'empiricist' view. Skinner (1957) was the first to carry out this empirical study and claimed that the child basically learns through imitation of the linguistic environment around her. According to Skinner's ...
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The aforementioned evolutionary model is a relatively novel concept. The following section will return to the more classical and empirically evidenced theories discussed earlier, beginning with the behaviourist view. The behaviourists argue that language development takes place even before birth and is part of the general learning process of a child. They only study behaviour that can be measured or observed, hence it is synonymous with the 'empiricist' view. Skinner (1957) was the first to carry out this empirical study and claimed that the child basically learns through imitation of the linguistic environment around her. According to Skinner's (1957) operant conditioning principles, when care-takers reinforce a particular behaviour in a child, she learns which behaviour is correct and which is not. Moreover, Skinner boldly attempts to account for the acquisition of syntax. He claims that the structure of a sentence consists of a line of associations between the words in the sentence, so if a child knows the words "dog" and "run" and hears them used together, such as "the dog is running", the child may imitate "dog run" and be rewarded by the care taker.
In an attempt to test the above 'classical' theories, new studies of heart deceleration (or reduction) have demonstrated that foetuses are capable of discrimination and some form of rudimentary cognition (Lecanuet et al., 1992). This particular study found that heart rate decelerated when the stimulus exposed to the foetus changed from the word 'babi' to 'biba'. This evidence then suggests that the foetus is capable of discriminating between phonetic stimuli, as measured by heart rate. Another study by Kuhl et al. (1992) provides further evidence of the affect of children's linguistic environment on their language development. Native Swedish and American 6 month old infants, were made to hear vowels which were specific to only their native language to test if they noticed a difference when the language was not their native one. Their reactions were strikingly different. Swedish infants responded when the English vowel came along but not when the Swedish one was heard, and vice versa. In other words, the infants, even at the age of 6 months had learnt not to pay attention to slight changes in speech sounds of their own language, but they were still able to distinguish it in another language. Although the children were too young to understand the meaning of what they heard, the speech of people around them had affected the development of their perceptual mechanisms. These results support the native language recognition hypothesis put forward by Moon et al. (1993).
Having considered the behaviourists argument, an evaluation of Chomsky's 'Universal Grammar' and other nativist theories will be presented below. Chomsky's basic question to the above is, how is it that a child can master the complexity and abstractness of language at such an under-developed stage in such a short time? Children are not taught language in a systematic manner; they are merely exposed to a stream of talk which may or may not be grammatical (Lewin, 1999). He also observed that the regular speech of adults is not as correct as it would be in a novel or in a play (poverty of stimulus); often it is ungrammatical and full of fragmented sentences (Chomsky, 1965). He, therfore, characterised everday adult speech as 'defective' and 'degenerate'. If this speech is all that the children hear, then it is quite intriguing how they learn the complex rules of grammar (Carlson et al., 2000). Given what he called the "poverty of stimulus", Chomsky argued that children must come into the world with fundamental rules of grammar hard-wired in their brains (Chomsky, 1957, 1965). This led many linguists to believe that the ability to learn language is innate. They proposed that a child's brain contains a "language acquisition device" which embodies rules of "universal grammar"; since each language has distinct expressions, the child has to learn the details, but the basics are already there (Chomsky, 1965; Lennenberg, 1967; McNeill, 1970). Simply put, the input largely underdetermines the linguistic representations of the adult grammar. This observed "poverty of stimulus" favours inherent mental structure in the learner (Hornstein & Lightfoot, 1981 cited in Lidz et al., 2003) and it is this structure that supports linguistic verbalisation beyond that which can be learnt from the input (Crain 1991; Pinker 1989 cited in Lidz et al., 2003).
Nevertheless, the nativist theory did not come without limitations. Chomsky's assumption that all languages are similar was rather impetuous. A study by Hebb et al. (1973) suggested that languages simply depict realities of the world. The interaction of people and their environment inevitably encounters the need for certain words to develop as adjectives, nouns, etc. Thus, all languages need to have words for elements that regularly require its usage. It may also be concluded that the LAD referred to, may be independently invented at different times across different cultures, since tools needed to hammer and chisel have also been invented, but not necessarily due to a 'tool making device' located in the brain. More recently, the nativist theory, particularly the "poverty of stimulus" argument, has been challenged by Pullum and Scholz (2002). Several researchers have contended against the idea that linguistic input is insufficient to account for linguistic representation (Brent & Cartwright, 1996; Seidenberg, 1997) and this input can be derived by general purpose learning mechanisms (Elman, 1990; Saffran et al., 1996). An experiment conducted by Lidz et al. (2003) produced evidence for the idea that the input to children does not contain sufficient information to support unaided learning. The results clearly show that syntactic knowledge could not have been gleaned exclusively from the input. The infants mastery of this aspect of syntax again contributes to the innate structure within the learner acquiring the grammar. They hold that a set of "representational presuppositions" inside the learner's mind serves "to structure available input" in a way that facilitates learning.
Pesetsky (???) has posed another intriguing question supporting the innate model. To Chomsky's problem of how babies learn language despite the poverty of stimulus, he asks why is it that languages which were not in historical contact, nevertheless have the same basic structure and properties. He further argues that there must be a "universal, invariant core of language" which we are born with that is easily triggered by environmental stimuli. Among the 500 languages studied by Cinque (???), languages do not only have similar properties, but are "identical" in all languages only because it is inscribed in our innate predesposition for language. His results lead him to believe that structure is just a frozen accident of evolutionary history, just as we are genetically endowed with one pair of eyes and five fingers instead of seven.
Meanwhile, Chomsky has been revising his theory of universal grammar with what he terms the Minimalist Program.(Lewin, 1999). In an attempt to resolve the tension between innate structure and behaviourist theories, Chomsky has softened his stand slightly by agreeing to certain 'minimum attributes' which are prerequisites for language development. But too much that is at stake here requires empirical questions. The environments role has not been undermined, but the nativist idea has simply been enforced for the reason that it is that predesposition that primarily orients a child to communicate.Without that predisposition, a child may even choose not to communicate even though her circumstantial needs will compel her to. Children in this physically healthy environment without language would still nonetheless attempt to explore a range of communicative activity (Goldin-Meadow & Mylander, 1990 cited in Reed, 1995). As this paper has attempted to argue throughout, the empirical evidence adduced in support of Chomsky's theory of language, is comprehensively significant, to say the least. There has to be a balance between acquiring the many complexities of languages and the limited set of structure that are present to do it. The bottom line is, despite Chomsky admitting some of his standard assumptions to be false, he, along with the writer, still believe that an innate device in the brain acquires grammar, it is not simply learnt from the 'environmental inputs'.
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PESETSKY (???)
CINQUE (???)
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