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.
National and regional identity in Spain
Over the past few decades, a concept known as the Catalan Countries ("Països Catalans") has developed as a strand of Catalan nationalism advocated by the Valencian writer Joan Fuster. This is the idea that Catalonia, Valencia, the Balearic Islands and a few other places in Spain and in other European countries are united by the fact that they share Catalan as a historic language, and are in this way distinct from the rest of Spain. In Valencia, however, reservations are frequently expressed about being included in this concept.