The variable competence model and sociolinguistic knowledge in interlanguage

Second language acquisition (SLA) research has given evidence that the natural route of development followed by second language (L2) learners does not manifest itself in a series of clearly delineated stages. Interlanguage (IL) theory needs to consider the variability inherent in language-learner language. Each new rule that enters and becomes part of the IL system is gradually extended over a range of contexts depending (i) on the learner's own ability to make use of it, i.e. the psycholinguistic dimension of language growth, and (ii) on the social contexts of languages use i.e. the social dimension of that growth. Since not all the variability found is haphazard and at least some of it is systematic, with definite patterns in it, this paper addresses the social dimension of systematic variability and the sources that cause this variation, according to Ellis's (1985a) Variable Competence Model.