Fifty Years of Second Language Acquisition Research: Critical Commentary and Proposal

Introduction. The article evaluates contemporary research on psycholinguistics and neurolinguistics to find answers related to why child first language (L1) acquisition relies on different processing methods compared to adult second language (L2) acquisition, and why an L2 can be complex for adults to learn. This paper is basically a critical appraisal of language acquisition (LA) research proposing new venues to explore. Aims. The primary goals of this article are to emphasize the need for treating the brain as a testable scientific hypothesis, rather than merely a philosophical theory and to illustrate the need to integrate L2, brain, mind and the learner at every moment to account for LA. Method and Results. To achieve these intriguing goals, previous research on psycholinguistics and neurolinguistics is critically reviewed. The review has shown that that the brain in SLA research has been treated simply as a philosophical theory. This, in my view, has serious impacts on the progress and development of the field in two ways: It causes the research to be held back by assumptions that have hardened into dogmas and act against open-minded thinking. It leads researchers to depend solely on learners’ performances (the actual use of language) to describe and explain the nature of the linguistic systems that L2 learners develop (competence) and to explain how an L2 is acquired. However, we all know that performance is not on all occasions a perfect reflection of competence (cf. Chomsky, 1965, 1988) These two points emphasize the need for treating the brain as a testable scientific hypothesis rather than merely a philosophical theory and exemplify the necessity of continuously integrating second language (L2), brain, mind, and the learner at every moment to explain both why learning occurs and why it fails to occur. Conclusions. The paper offers a critical appraisal of previous research into psycholinguistics and neurolinguistics. It argues that the brain in second language acquisition (SLA/L2A) research has been treated merely as a philosophical theory for a long time, resulting in findings that lack actual neurolinguistic analysis. The paper suggests that theoretical explanations for why children acquire L1 faster and more easily than adults acquiring L2 align with recent testing of the brain, revealing differences in brain activity waves between early and middle childhood compared to adulthood. This indicates distinctions in language acquisition between children and adults in terms of brain wave activity, size of grey matter, and other factors.