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.
Romance languages
Catalan is the official language of Andorra. In Spain, it is co-official with Spanish (Castilian) in Catalonia, the Valencian Community, and the Balearic Islands, and it is recognized, but not official, in La Franja, and in Aragon. In addition, it is spoken by many residents of Alghero, on the island of Sardinia, and it is co-official in that city. Galician, with more than a million native speakers, is official together with Spanish in Galicia, and has legal recognition in neighbouring territories in Castilla y León. A few other languages have official recognition on a regional or otherwise limited level; for instance, Asturian and Aragonese in Spain; Mirandese in Portugal; Friulan, Sardinian and Franco-Provençal in Italy; and Romansh in Switzerland.