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
Today, Catalan is one of the three official languages of autonomous community of Catalonia, as stated in the Catalan Statute of Autonomy; the other two are Spanish, and Occitan in its Aranese variety. Catalan has no official recognition in "Northern Catalonia". Catalan has official status alongside Spanish in the Balearic Islands and in the Land of Valencia (where it is called "Valencian"), as well as Algherese Catalan alongside Italian in the city of Alghero and in Andorra as the sole official language.