With hundreds of the world’s languages now in danger, the need for effective methods of language revitalization has never been greater. Yet most efforts fall short of their objective. The central point of this chapter is that language revitalization is possible only if it is possible to create or maintain the conditions under which language acquisition can take place. Two key issues are explored in detail—the question of how children acquire (and lose) language, and the question of how bilingualism can be pursued as a key component of language revitalization. The answers to both questions have certain features in common, including acknowledgment of the advantages that arise from exposure to the language at a young age, a recognition of the importance of ample, high-quality input, and the need for ongoing opportunities to use the language in a range of communicative situations.