This essay explores the relationship between democratic political theory and the reality of linguistic diversity in contemporary political communities. After suggesting a distinction between "liberal" and "participatory" democratic theories, and asserting that there have been fruitful explorations of linguistic diversity in relation to the former, the essay claims that there has been a virtual absence of critical examination of the implications of linguistic diversity for participatory democracy. The essay explores the implications of "ontological multilingualism" for three purported advantages of participatory democracy: the legitimation advantage, the common good advantage, and the human flourishing advantage. After examining challenges to the accommodation of linguistic diversity by participatory democracies, the essay concludes with suggestive comments on how these challenges might best be approached.