The Composite Abstract Lexical Structure of Interlanguage and Its Implications for Second Language Acquisition

This paper explores the nature of interlanguage with a focus on its lexical structure in relation to second language acquisition. The lexical structure of any language is assumed to be ‘abstract’ in that the mental lexicon contains ‘lemmas’, which are pieces of information about individual lexemes at three abstract levels: lexical-conceptual structure, predicate-argument structure, and morphological realization patterns. The abstract lexical structure of IL is assumed to be ‘composite’ in that during the process of second language acquisition several linguistic systems are in contact, each of which contributes different amounts to interlanguage (i.e., the developing linguistic system). This study claims that lemmas are language-specific and the bilingual mental lexicon contains cross-linguistic lemmas at each of these abstract levels. It further claims that bilingual lemmas are in contact in interlanguage production, and it is cross-lemma variations in the composite abstract lexical structure of interlanguage which induce learner errors. Naturally occurring interlanguage production data for the study include several first and second language pairs. Based on the research findings, this study concludes that interlanguage variations are driven by an incompletely acquired abstract lexical structure of a target language and offers some implications for second language acquisition.