This article considers in detail the choosing of a language for the liturgy and sermons in Roman Catholic parishes in Belarus. The choice of the Belarusian language is part of a deliberate nation-building policy by the Catholic Church. Moreover, a whole network of local peculiarities, historical stereotypes, and political attitudes is concealed beneath the unified cover of a preference for the use of the Belarusian language. Based on interviews with clergy and religious activists, the article shows that the Roman Catholic Church repeatedly works out compromise solutions that allow it to adapt to the pressures of the state and believers going through a process of contradictory and conflicting nation-building.