9.4 Explaining second language acquisition
In the previous sections we have discussed what second language acquisition is, what factors affect second language acquisition, and how learners' language is analized. This section surveys the theories that account for second language acquisition. How does (second) language acquisition take place? This question still puzzles linguists, psycholinguists, neurolinguists and other cognitive scientists. Reading the literature of SLA, one can find various models and theories that purport to explain the complex process of SLA. In this section we will introduce three classes of theory --- nativist, environmentalist and functionalist theories.
Nativist theories are those that attempt to explain acquisition on the basis of assuming an innate biological endowment that makes learning possible. A number of models have been proposed since the 1960s, which were prompted by Chomsky's hypothesis that there is a language acquisition device (LAD) in the human brain. One of the best known and influential nativist theories is Krashen's Monitor Theory. In a series of books and articles published by Krashen between the mid 1970s and the early 1980s, the theory was put forward in the form of five hypotheses: the Acquisition-Learning Distinction, Natural Order, Monitor, Input, and Affective Filter. The acquisition-learning distinction is the corner-stone of Krashen's theory. ‘Acquisition’ occurs subconsciously as a result of participation in natural L2 communication. ‘Learning’is the result of conscious study of the formal system of the language. It is assumed that the two kinds of knowledge are stored in different areas of the LAD and thus play different roles in linguistic performance. ‘Acquired’ knowledge serves as the source for automatic production of speech, whereas ‘learnt’ knowledge is available for use only in monitoring linguistic production. This idea can be illustrated by his model:
A model of second language performance (Krashen and Terrell 1983: 30)
As a corollary of this, what can be done in second language teaching is only provide comprehensible input just beyond the learner's present level. If the input goes through the affective filter, then acquisition will take place.
The Monitor Model is quite provoking. Some scholars took issue with Krashen regarding whether learnt knowledge can be turned into acquired knowledge given adequate practice. Others argue that the model merely explains what contributes to performance but does not explain what the learner does with regard to input. Gass (1988) distinguishes input from intake and proposes a process model as shown below:
Figure 9.2 A process model of SLA (Adapted from Gass (1988))
According to Gass (1988), noticed input is the first stage of acquisition --- a passing through of the initial data. Not all noticed input is comprehended and not all comprehended input becomes intake. Intake is seen as “a process which mediates between target language input and the learner's internalized set of rules” (Gass 1988: 206). As the above figure shows, explicit knowledge contributes to output. Output can become input through interaction. The model proposed by Gass accounts for the fact that SLA is a process prompted by innumerous cycles of experience in L2 communication.
Environmentalist theories hold that experience is of more importance than innate contributions in learning a second language. This view is represented by the Acculturation Model. Acculturation is “the process of becoming adapted to a new culture” (Brown 1980: 129). The central premise of the model is expressed by Schumann (1978: 34): “... second language acquisition is just one aspect of acculturation and the degree to which a learner acculturates to the target language group will control the degree to which he acquires the second language.” Acculturation is determined by the degree of social and psychological distance between the learner and the target language culture. The model was constructed on the basis of observations of an adult learning English as a second language in the U.S.A. Where the target language is learned as a foreign language, it is questionable whether the Acculturation Model is still effective in explaining the acquisition process. In addition, social factors are after all external factors, which are indirect to the process of SLA.
Functionalist theories attempt to explain SLA from interpersonal as well as intrapersonal perspectives. Halliday (1975) has shown that the development of the formal devices for realizing basic language functions grows out of the interpersonal uses to which language is put. Language is as it is because it fulfills the functions. Naturally, language acquisition takes place in the process of learning to communicate. As Hatch (1978: 404) put it: “One learns how to do conversations, one learns how to interact verbally, and out of this interaction, syntactic structures develop”.
Parallel to this functional linguistic perspective, there emerges a neurofunctional perspective, which attempts to characterize the neurolinguistic information processing systems responsible for the development and use of language. “The basic premise of a neurofunctional view of SLA is that there is a connection between language function and the neural anatomy” (Ellis 1985: 271). The difference between this view and a nativist theory lies in the assumption that there is no single “black box” (like the LAD assumed by Chomsky and his followers) for language in the brain. It is hardly possible to identify precisely which areas of the brain are associated with language acquisition. Neurofunctional accounts of SLA recognize the contribution of both the left and the right hemispheres of the brain. There has been the hypothesis that the right hemisphere is associated with formulaic speech, the left hemisphere is associated with creative language use, including analytic processing. There have also been suggestions that different levels of language processing (pronunciation VS. grammar, for example) are completed by different neural mechanisms. The evidence is the fact that learners may be native-like in grammar but not in pronunciation. These hypotheses or suggestions await verification.
