Willoughby, L.J.V., In press, Language maintenance, in Handbook of Pragmatics, eds Jan-Ola Östman & Jef Verscheuren, Amsterdam, John Benjamins Introduction Language maintenance and shift research forms a sub-field of linguistics with a complex history. Inspired at least in part by the Germanic research tradition into Sprachinseln (language enclaves that resist shift to the language of the surrounding society for generation; see Pauwels 2016) from the mid-1960s onwards we see an increasing movement of scholars documenting language practices among migrant families and communities – especially in the US (e.g. Clyne 1968; Fishman 1966; Lopez 1978; Skrabanek 1970). At the same time we see a parallel growth in research with indigenous communities around issues of language endangerment and reclamation (for an overview see Pauwels 2016). While the terms ‘language maintenance and shift’ have historically been used much more in reference to research on migrants, rather than indigenous groups, it is clear that many of the issues and theories are applicable in both contexts, and thus this entry will discuss both where relevant. Language maintenance and shift are generally understood as describing patterns around a person or group’s habitual language practices (with terms like code-switching and translanguaging being used to describe elements of language mixing in specific utterances – CROSS REF TO CODE-SWITCHING ENTRY). However, researchers use the terms in slightly different ways. Clyne (2003:20) reminds us that what a research means by ‘language shift’ might encompass changes in any of the following: • language use at the community or individual level • the main language used • the dominant language or individuals or groups • the language used in one or more specified domains