Spain
As a percentage of the general population of all Spain, Spanish is natively spoken by 74%, Catalan by 17%, Galician by 7% and Basque by 2% of all Spaniards. Occitan is spoken by less than 5,000 people, only in the small region of "Val d'Aran".
Other Romance minority languages, though not official, have special recognition, such as the Astur-Leonese language ("asturianu", "bable" or "llionés") and Aragonese ("aragonés") in Aragon.
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.