In Language Death David Crystal looks at present and future threats to languages - and at what can be done to counter them. Crystal's relatively unemotional, reasonable, and balanced approach is unlikely to ever gain him the acclaim of more populist science writers, but he is always readable and informative and Language Death is no exception. A succinct overview with a good selection of examples and case studies, it has something for anyone involved with either linguistics or indigenous cultural survival.
Crystal begins by looking at the scale of the threat to minority languages.
None of these are likely to convince either aggressive monolingualists or the apathetic, but Crystal includes some thought-provoking details and quotes. Obviously a language dies if all of its speakers die as the result of genocide or natural disasters, or are scattered in such a way as to break up the language community. This process is broad and complex, but one major factor is negative attitudes to a language, both in government policy and local communities.