In order to understand why languages become endangered, linguists must shift from documenting the last fluent speakers to documenting the larger ecology of language use in an area. The papers in this special issue all address different aspects of documenting language multilingualism. They address three related topics: (1) consideration of the state of multilingualism in endangered language ecologies; (2) tools and methods for transcribing, annotating, analyzing and presenting multilingual corpora; and (3) methods in documenting and studying language contact in process.