There are a few hundred known sign languages around the world, and in such language communities, multilingualism is the norm. This multilingualism traverses modalities: signed, written, and, in some cases, spoken forms of language. Such a linguistic landscape inevitably leads to various forms of language contact between languages, including contact between two or more signed languages (characterised by lexical borrowing), signed language and spoken language (characterised by mouthings), and signed language and written language (characterised by fingerspelling, initialized fingerspelling). This chapter also covers sign language interference, code switching and code mixing, and the concept of bimodal bilingualism. The chapter concludes with a discussion of pidginization and creolization of sign languages and sign language endangerment, as well as general comments on the characteristics of contact between signed languages.

In this chapter, we review how economists and linguists have problematized the relationship between economy and language, focusing on their methodologies, theoretical toolboxes, and ideologies. One of the striking differences lies in the ways they conceptualize languages, viz., as strictly denotational for economists but both denotational and indexical for linguists. We show that by approaching them as abstract, asocial, ahistorical, and statistically measurable entities, economists treat languages as resources whose economic consequences for individuals or societies can simply be derived from their intrinsic nature. By contrast, examining languages as practices grounded in their sociohistorical ecologies, linguists have been more interested in the valuation of some languages as capitals that can outweigh others economically or symbolically. Overall, we highlight the interdisciplinary nature of “economy and language” as a research area, showing how complex it is and how productive it should be to build an intellectual bridge between the two disciplines.