Most of the 7,000 languages spoken in the world today will vanish before the end of this century, taking with them cultural traditions from all over the world, as well as linguistic structures that would have improved our understanding of the universality and variability of human language. This book is an accessible introduction to the topic of language endangerment, answering questions such as: what is it? How and why does it happen? Why should we care? The book outlines the various causes of language endangerment, explaining what makes a language 'safe', and highlighting the danger signs that threaten a minority language. Readers will learn about the consequences of losing a language, both for its former speech community and for our understanding of human language. Illustrated with case studies, it describes the various methods of documenting endangered languages, and shows how they can be revitalised.