The paper seeks to assess the consequences of cultural diversity for European polity-building by focusing on the language issue. What does the European Babel mean for the project of transnational political integration ? To what extent has the shaping of the European language regime become a declared goal on the agenda of the EU ? In contrast with precedent patterns of nation-state formation, the present situation in Europe offers only few reasons to believe that some cultural standardization could be achieved by putting major political restrictions on multilingualism. Deliberate attempts at setting the institutional foundations of a culturally integrated European public sphere may end up producing unintended outcomes and lead to anti- European mobilizations striving for the protection of cultural difference. Hence, a political community of Europeans will not be based on a unitary and homogeneous public sphere, but rather reflect a complex mosaic of different cultural identities with cross-cutting political loyalties. In this context, cultural and linguistic diversity will be institutionalized, institutionalized, but to varying degrees and with different implications at different political levels.