The one language-one nation ideology of language policy and national identity is no longer the only available one worldwide (if it ever was). Multilingual language policies which recognize ethnic and linguistic pluralism as resources for nation-building are increasingly in evidence. These policies, many of which envision implementation through bilingual intercultural education, open up new worlds of possibility for oppressed indigenous and immigrant languages and their speakers, transforming former homogenizing and assimilationist policy discourses into discourses about diversity and emancipation. This paper uses the metaphor of ecology of language to explore the ideologies underlying multilingual language policies, and the continua of biliteracy framework as ecological heuristic for situating the challenges faced in implementing them. Specifically, the paper considers community and classroom challenges inherent in implementing these new ideologies, as they are evident in two nations which introduced transformative policies in the early 1990s: post-apartheid South Africa's new Constitution of 1993 and Bolivia's National Education Reform of 1994. It concludes with implications for multilingual language policies in the United States and elsewhere.