The awareness of endangered languages is part of a larger picture, arising out of social and political changes in the past decades. This awareness has brought about many changes in linguistics. This chapter reviews background material, including the language situation around the world, causes of language endangerment, reasons why language endangerment has garnered the concern that it has in the past few decades, and responses to language endangerment. The increasing recognition among linguists of how many languages were endangered encouraged a greater emphasis on fieldwork. This in turn promoted discussions of language documentation, language revitalization, and the ethics of fieldwork. The nature of language is much discussed in the anthropological responses to the endangerment literature. Current methods of language documentation focus on audio and video recordings of natural speech, narrative and conversation, as well as structured elicitation.