Languages of Catalonia
The main cause of Spanish and Catalan social bilingualism in modern Catalonia was large-scale migration from the rest of Spain during the 20th century, as Catalonia started a significant industrialization which demanded an increased workforce from elsewhere. Spanish has historically been spoken among a minority of civil servants born in other regions in Spain and among segments of the wealthiest bourgeoisie. Spanish has also been spoken as a second language by most Catalans, as it has been the only official language over long periods since the eighteenth century.
Political divisions of Spain
The official names of the autonomous communities can be in Spanish only (which applies to the majority of them), in the co-official language in the community only (as in the Valencian Community and the Balearic Islands), or in both Spanish and the co-official language (as in the Basque Country, Navarre and Galicia). Since 2006, Occitan—in its Aranese dialect—is also a co-official language in Catalonia, making it the only autonomous community whose name has three official variants (Spanish: "Cataluña", Catalan: "Catalunya", Occitan: "Catalonha").