The principle of cultural and linguistic homogeneity, upon which the organization of modern nation-states is predicated, is becoming increasingly hard to defend and maintain. At the demographic level, nation-states comprise (indeed, have always comprised) a variety of different cultural and linguistic groups. These include, alongside majority populations, indigenous peoples and other national minorities, as well as migrant communities. This long-standing demographic diversity has also increased markedly in modern times, particularly with patterns of increased migration and the forced relocation of refugees. These demographic changes have, in turn, placed increasing pressure on the public policies of nation-states which have historically been inimical or formal recognition of cultural and linguistic diversity. As a result, nation-states are having to address more seriously the 'politics of multiculturalism' - that is, the degree to which the languages and cultures of so called 'minority' groups can be (or should be) accorded recognition in the public domain. This also necessarily involves addressing directly issues of bilingualism and multilingualism and their implications for language and education policy and practice. This paper explores these broader debates in specific relation to Aotearoa/New Zealand which itself has seen a marked increase in migration, and attendant cultural and linguistic diversity, over the last ten years. Debates on multiculturalism, and their implications for public policy, are contentious enough in themselves, but are further complicated in Aotearoa/New Zealand by prior bicultural commitments to Maori. Can multicultural/multilingual commitments be extended without compromising, or undermining biculturalism? What are the specific implications of this potential dialectic between biculturalism and multiculturalism for the further development of language and education policy in Aotearoa/New Zealand? The paper will attempt to develop a set of general principles as a basis for moving these debates forward, drawing on discussions of language rights, and language planning and policy, as well as recent developments in international law. Specific implications for language education will also be discussed.