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.
Catalans
The Catalan language is a Romance language. It is the language closest to Occitan, and it also shares many features with other Romance languages such as Spanish, French, Portuguese, Aragonese, and Italian. There are a number of linguistic varieties that are considered dialects of Catalan, among them, the dialect group with the most speakers, Central Catalan.