Autonomous communities of Spain
Spanish legislation, most notably in the Statutes of Autonomy of the bilingual communities, use the term "own language", or "language proper to a community", to refer to a language other than Spanish that originated or had historical roots in that particular territory. The Statutes of Autonomy of the respective autonomous communities have declared Basque the language proper to the Basque Country and Navarre, Catalan the language proper to Catalonia, the Balearic Islands and the Valencian Community—where it is historically, traditionally and officially known as Valencian—and Galician to be the language proper to Galicia. There are other protected regional languages in other autonomous communities. As a percentage of total population in Spain, Basque is spoken by 2%, Catalan/Valencian by 17%, and Galician by 7% of all Spaniards. A 2016 Basque Government census revealed 700,000 fluent speakers in Spain (51,000 in Basque counties in France) and 1,185.000 total when passive speakers are included.
Burgos
Spanish, also called Castilian, originated in Castile and spread throughout the Crown of Castile's possessions following the reconquista. It was eventually dispersed throughout the Spanish empire following the conquest and colonization of the Americas, and Spain after the union of the Catholic Monarchs's kingdoms being co-spoken with other languages. Of the many different variations and dialects found throughout the world, it's argued that the purest Spanish can be found in the region of Burgos due to the fact that the language first developed here in the 10th-century.