Up to ninety percent of humanity's traditional languages and cultures are at risk and may disappear this century. While language endangerment has not achieved the publicity surrounding environmental change and biodiversity loss, it is just as serious, disastrously reducing the variety of human knowledge and thought. This book shows why it matters, why and how it happens, and what communities and scholars can do about it. David and Maya Bradley provide a new framework for investigating and documenting linguistic, social and other factors which contribute to languages shifting away from their cultural heritage. Illustrated with practical in-depth case studies and examples from the authors' own work in Asia and elsewhere, the book encourages communities to maintain or reclaim their traditional languages and cultures.