Andean Aymara

Nicholas Evans, head of the  Department of Linguistics, Division of Society and Environment of the Research School of Pacific and Asian Studies (RSPAS) at the Australian National University, has written a book called Dying Words (published by OUP).  The LinguistList published a glowing review and summary by Daniel Hieber, which makes the book sound like a good read:

Evans does an outstanding job laying out the framework for discussion, and keeping to that framework throughout the book. He does this in a thought-provoking manner, avoiding classic examples in favor of his own, often better ones. _Dying Words_ has its place among books for a general audience on linguistics and makes a persuasive case for preserving endangered languages
everywhere.

Check it out.

Update: I found this book and though it looks very well-written, it is definitely geared more towards undergraduates or people interested in moving from studying conventional linguistics or anthropology to endangered languages