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
As of 2011, 95% of the population were able to understand Catalan, and 73% could speak it. In 2007, 32% named Catalan as the primary language that they actually did speak, against 50% for Spanish (Castilian); 7% spoke the two languages equally. The ethnolinguistic composition of the population has been heavily affected by extensive immigration from non-Catalan speaking parts of Spain, much of it associated with rapid growth in industry, since the late 19th century and more particularly between 1950 and 1975.