This paper revisits a classic question for scholars of government and politicians: how is the behavior of cultural or ethnic groups affected by the formal institutions that regulate their rights? While the literature has demonstrated that state-sanctioned discrimination or forced assimilation into a majoritarian identity often produces backlash among minority members, I study the consequences of accommodating minority rights, focusing on one important dimension: the status of minority language. I exploit a regional linguistic reform in post-transition Spain: in 1986 the Spanish province of Navarra allocated municipalities into one of three linguistic zones, each with a different degree of normalization of the Basque language in the public sphere. I study the effects of linguistic regimes on the identity choices of Basque and Spanish speakers, the making of group boundaries, and political participation. With granular sub-municipal data and a Geographic RDD, I find that crossing the administrative border between the Spanish-only and the bilingual regime zone increases the vote shares of Basque nationalist parties, at the expense of traditional Spanish parties. With a Difference-in-Differences design, and historical election data, I study how the reform induced diverging patterns in voting behavior across formerly politically homogeneous areas. I then track identity choices across generations with data on Basque names and surnames in municipal election lists and with surveys on linguistic preferences. Finally, I use machine learning tools to classify the language of streets and toponyms, and school-level data on the offer of the language of instruction. I find that today the linguistic reshaping of the public space remains contested.