Constructing interlanguage: building a composite matrix language

Treating interlanguage as language contact results in an explanatory account of second-language acquisition (SLA). The proposed model is informed by three sets of assumptions. First, lexical structure is composed of levels or substructures; the relevant levels are lexical-conceptual structure, predicate-argument structure, and morphological-realization patterns (Talmy 1985; Jackendoff 1990; Myers-Scotton and Jake 1995). Second, the distinction between content and system (i.e. functional) morphemes, developed in the matrix language frame model of intrasentential code switching (Myers-Scotton 1993), determines how lexical items can contribute to building the interlanguage grammatical system. Two types of system morphemes are recognized: conceptually activated system morphemes and structurally assigned system morphemes (Bock and Levelt 1994 ; Jake and Myers-Scotton 1996). Finally, the matrix-language and embedded-language distinction structures interlanguage. In SLA an INTENDED matrix language, the target language, and a DE FACTO matrix language, the developing linguistic competence, are recognized. The L1 acts as an embedded language. Interlanguage structures are projected by lexical substructures of the three linguistic systems in contact. Principles structuring language contact and the nature of the grammatical elements projecting lexical structure determine what types of grammatical structures each system can contribute and how they are combined into a developing composite matrix language