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.
Linguistic features of Spanish as spoken by Catalan speakers
The Spanish language is widely spoken in most of the Catalan-speaking territories, where it is partly characterized by language contact with the Catalan language. These territories are: Catalonia, the Valencian Community (except some inland areas which are only Spanish-speaking), the Balearic Islands, Andorra, and the easternmost areas of Aragon. This linguistic contact is encouraged by the fact that almost all of the Catalan speakers in these regions are Catalan–Spanish bilingual to a greater or lesser extent.