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
The number of people known to be fluent in Catalan varies depending on the sources used. A 2004 study did not count the total number of speakers, but estimated a total of 9–9.5 million by matching the percentage of speakers to the population of each area where Catalan is spoken. The web site of the Generalitat de Catalunya estimated that as of 2004 there were 9,118,882 speakers of Catalan. These figures only reflect potential speakers; today it is the native language of only 35.6% of the Catalan population. According to "Ethnologue", Catalan had four million native speakers and five million second-language speakers in 2012.
The most important social characteristic of the Catalan language is that all the areas where it is spoken are bilingual in practice: together with the French language in Roussillon, with Italian in Alghero, with Spanish and French in Andorra and with Spanish in the rest of the territories.