Who speaks what language to whom and when?

Multilingual settings differ from each other in so many ways that every student of multilingualism must grapple with the problem of how best to systematize or organize the manifold differences that are readily recognizable. This chapter is primarily limited to a formal consideration of several descriptive and analytic variables which may contribute to an understanding of who speaks what language to whom and when in those settings that are characterized by widespread and relatively stable multilingualism. It deals primarily with “withingroup (or intragroup) multilingualism” rather than with “between-group (or intergroup) multilingualism,” that is with those multilingual settings in which a single population makes use of two (or more) separate codes for internal communicative purposes. As a result of this limitation, general knowledge of mother tongue and other tongue may be ruled out as an operative variable since most individuals could communicate with each other quite easily in either of the available languages. It seems clear, however, that habitual language choice is far from being a random matter of momentary inclination, even under those circumstances when it could very well function as such from a purely probabilistic point of view. “Proper” usage, or common usage, or both, dictate that only one of the theoretically co-available languages will be chosen by particular classes of interlocutors on particular occasions.