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.
Principality of Catalonia
On several occasions during the first third of the 20th century, Catalonia gained and lost varying degrees of autonomy, recovering, after the proclamation of the Second Spanish Republic in 1931, the Generalitat as an institution of self-government, but as in most regions of Spain, Catalan autonomy and culture were crushed to an unprecedented degree after the defeat of the Second Spanish Republic (founded in 1931) in the Spanish Civil War (1936–1939) which brought Francisco Franco to power. Public use of the Catalan language was again banned after a brief period of general recuperation.