The Composite Nature of Interlanguage as a Developing System

This paper explores the nature of interlanguage (IL) as a developing system with a focus on the abstract lexical structure underlying IL construction. The developing system of IL is assumed to be ‘composite’ in that in second language acquisition (SLA) several linguistic systems are in contact, each of which may contribute different amounts to the developing system. The lexical structure is assumed to be ‘abstract’ in that the mental lexicon contains abstract elements called ‘lemmas’, which contain information about individual lexemes, and lemmas in the bilingual mental lexicon are language-specific and are in contact in IL production. Based on the research findings, it concludes that language transfer in IL production should be understood as lemma transfer of the learner's first language (L1) lexical structure at three abstract levels: lexical-conceptual structure, predicate-argument structure, and morphological realization patterns, and IL construction is driven by an incompletely acquired abstract lexical structure of a target language (TL) item.