The interest in the links between multilingualism and economic activity is relatively recent. Up until the early 1970s, the use of different languages or variants of one language was generally seen as raising (in addition to linguistic questions) mainly sociological, and occasionally political or legal, issues. Along with the notion that linguistic processes are deeply embedded in social ones came the realization that economic activity could be seen as a “domain” in the sociolinguistic sense of the term, and that taking this domain into account is important to the understanding of the dynamics of language learning and language use. In addition, economic activity is a highly relevant locus in which to observe multilingual interaction.