In this piece, I tackle a current subject of popular controversy - whether growing multilingualism in the United States imperils the future of American democracy. I offer a positive theory, centered on the value of democratic participation, of how a society like the United States should approach the multilingualism of its population. I conclude that embracing bilingualism in individuals and multilingualism in society is more likely to make linguistic pluralism socially functional and to sustain the vitality of public and social institutions than demanding public monolingualism. I begin by demonstrating that current approaches to language diversity in constitutional democracies, including our own, are largely remedial in nature. They focus either on ensuring the survival of particular minority groups historically present and marginalized in a given nation-state, or on helping immigrants overcome language barriers as they assimilate into the dominant language of the society in question. On its own, this remedial conception cannot ensure that linguistic diversity complements, rather than undermines, democratic institutions, because it does not account for the variety of linguistic interests present in a multiethnic society. I then address this limitation by offering an alternative, participatory theory of language difference. I base my conception of participation on principles of decentralized decisionmaking. This focus requires considering how to expand the individual's associative options and improve access to the mid-level social institutions where we live out most of our lives, such as the workplace and the public schools. In accommodating speakers of multiple languages in a given institution, we should focus on promoting social investment by individuals and groups, as well as preserving individual control over matters of deeply personal concern, rather than on the survival of particular languages or cultures. In developing this framework, I draw from the experiences of other multilingual societies and legal systems, but I present the United States as a case study to explain what a participatory approach would look like in practice. I focus on the major sites of language conflict in the United States - the political arena, the debate over official English, the workplace, and the public schools - and argue that a multilingual understanding of these sites and the legal rules that structure them best promotes participation.