Why does Renan exclude language from his definition of the nation in his seminal speech What is a nation? (1882)? The article argues against that exclusion by showing that it is philosophically unnecessary and historically problematic. There is a strong French tradition, established by the language politics of the French Revolution, that links nation to language. According to the Jacobins, the nation, i.e. the new democratic sovereign, must have one language for communicative and cognitive reasons. This conviction remains the basis of language-political activities today and creates tensions in the actual questione della lingua in Europe.
Keywords: European multilingualism, French Revolution, Génie de la langue, Language politics, Nation, National language, Renan.