The success of programs that are focused on revitalizing an endangered language depends on careful implementation. This paper examines four common mistakes that are made when linguists and anthropologists get involved with documenting endangered languages or participating in revitalization efforts: a failure to appreciate the complexity of the notion of "the community"; an overly simple understanding of the notion of "the language"; a neglect of the social dynamics and needs that underlie language use; and assuming too much control of the revitalization efforts. In the process of laying out these issues, a framework for how cultural outsiders can participate in an endangered language project will emerge. Fundamental to this framework is the recognition that language is a social practice, and as a consequence, working with an endangered language entails engagement with a range of complex, and often countervailing, social dynamics.