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 manual alphabet
The Catalan manual alphabet is used in Catalan Sign Language but wasn't officially recognized as one of Catalonia's official languages until 3 June 2010 when Law 17/2010 of the Catalan sign language (LSC) was approved by the government. The Catalan manual alphabet is single-handed and is extremely similar to the Spanish manual alphabet. As a result, people who use Spanish Sign Language can understand approximately up to 80% of the Catalan sign language.