Since the inception of the discipline of linguistics, linguists have been concerned with describing and documenting languages previously unknown to science. Starting with Franz Boas in the early 1900s, descriptive linguistics became the main strand within American linguistics until the rise of formal structural linguistics in the mid-20th century. The rise of American descriptive linguistics was caused by the concern with describing the languages of indigenous peoples that were (and are) rapidly moving toward extinction. The ethnographic focus of the original Boasian type of descriptive linguistics occasioned the development of disciplines such as Sociolinguistics, anthropological linguistics, and linguistic anthropology, disciplines that investigate the relations between language, culture, and society.
The emphasis on linguistic description and documentation has since become more important outside of North America as well, as the documentation of rapidly dying indigenous languages has become a primary focus in many of the worlds' linguistics programs. Language description is a work intensive endeavour usually requiring years of field work for the linguist to learn a language sufficiently well to write a reference grammar of it. The further task of language documentation requires the linguist to collect a substantial corpus of texts and recordings of sound and video in the language, and to arrange for its storage in accessible formats in open repositories where it may be of the best use for further research by other researchers.^[16]