Interlanguage

Abstract At a time when no systematic research was being conducted on second language acquisition, Selinker proposed that a linguistic system (interlanguage, or IL) underlies the learner language produced by adults when they attempt meaningful communication using a language they are in the process of learning (target language). He called for research to compare the structure of that learner language with the structure of the learner's native language and the target language, and to identify the psycholinguistic processes that shape interlanguage over time. This call initiated a flood of research studies and the establishment of the field of second language acquisition (SLA). This entry defines the essential elements of the interlanguage hypothesis as proposed in 1972, including the five psycholinguistic processes Selinker hypothesized as possibly influential: native language transfer, overgeneralization, transfer of training, strategies of communication, and strategies of learning; Selinker's controversial proposals that all interlanguages fossilize; and the claim that the relevant data for the study of interlanguage should be restricted to learner language produced during meaningful communication. The entry reviews the evolution of the interlanguage hypothesis in relation to several themes: the expansion of the hypothesis to apply to learners of all ages and to view IL as a natural language that obeys principles of universal grammar, and the exploration of the impact of social context and agency on IL psycholinguistic processes (including processes of fossilization and crosslinguistic influence). The basic assumption that interlanguage is systematic continues to underlie data collection and data analysis across the field of SLA.