This dissertation is a pioneering exploration of how the relationship between individuals’ native tongue(s) and the state’s official language(s) influences citizens’ attitudes toward the political system. First, using data from the 7th wave of the World Values Survey, my research finds robust evidence that, although speaking the official language strengthens attachment to the country, it simultaneously tends to reduce support for the regime and its specific core institutions. Moreover, even when citizens are not proficient in the official language, speaking a language that is linguistically similar to the official language increases national attachment but decreases support for the regime and its institutions. Furthermore, the effects of language are shown to be more powerful in explaining individual variations in political attitudes than most factors traditionally considered in the field. Next, using Round 4 of the Afrobarometer in Sub-Saharan Africa, I examine how multilingualism and the type of state language (colonial vs. indigenous) complicate these effects. The findings reveal that, in such contexts, the effects of language are more nuanced and vary across first and second languages, types of state languages, and different political attitudes. Finally, using nationally representative survey data from China, I confirm that linguistic variations, even at the dialectal level, still significantly influence public political attitudes. Additionally, I find the existence of a dialect-based political attitude field, where individuals speaking closely related dialects tend to converge in their political views. This dissertation contributes to the research on public opinion by shedding light on the profound yet often overlooked ways in which linguistic differences shape political attitudes, while also contributing to political science and social science at large by highlighting the salient role of language in political and social life, which deserves closer attention in light of current increasingly multilingual and multicultural trends.