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.
Catalan language
Standard Catalan, virtually accepted by all speakers, is mostly based on Eastern Catalan, which is the most widely used dialect. Nevertheless, the standards of the Valencian Community and the Balearics admit alternative forms, mostly traditional ones, which are not current in eastern Catalonia.