One of the most intractable issues in the field of second-language acquisition (SLA) research has been the attempt to identify the role of social context in influencing (or not) the process of acquisition of a second language. The central question has been whether a theory of SLA must account only for the psycholinguistic processes involved in acquiring an interlanguage (IL), or, alternatively, whether social and sociolinguistic factors influence those psycho-linguistic processes to such an extent that they too must be included in such a theory. It seems very clear that SLA is a psycholinguistic process. But to what extent are those psycholinguistic processes affected by social context? In 1985, Selinker and Douglas proposed a construct of ‘discourse domains’ to show how social and psycholinguistic processes might be included in a theory of inter-language; Young (1999) reviews that proposal and a recent attempt to test it, concluding that the results are still uncertain. After 15 years, this is still a lively issue in the field of SLA. Indeed, it is becoming a source of increasing conflict both within the field of SLA and within such areas of applied linguistics as second/foreign language teaching and second/foreign language teacher training. In this article, I will briefly summarize the problem, and review and summarize the current evidence being brought to bear upon this issue in the SLA research literature.