Language policy and language politics are rarely about language as such but always about policy and politics. Nowhere is this better illustrated than in the trajectories of Occitan and Catalan, two languages adjacent on the Romance dialect continuum and spoken in Southern France and Eastern Spain. Occitan is a language which has almost disappeared from daily use; Catalan is a language which is a medium in all domains of Catalonia’s public life and in many Catalan homes. How this divergence between language practice in these neighbours has come to pass is interesting, given how similar much of their past history has been, their connections, the parallels in their culture prior to the Modern period. The survival and vigour of Catalan and the practical demise of Occitan appear to be the direct result of different approaches to building a modern state in France and Spain. In France, economic benefit and social mobility reconciled the periphery to strong assimilatory pressure from the centre. In Spain, the central elite was less permeable and the periphery sought economic advantage and political power outside the capital. Assimilation and exclusion are at the heart of the different language choices and practices in the two states.