The extreme northwest corner of Spain is called Galicia. Tbe
official language is Spanish and I feel comfortable saying everyone
can use Spanish. However, they do have their own language called
Galician, or Gallego, which they use orally.
Wikipedia states "Modern Galician and modern Portuguese are
descended from a single Latin-derived language which linguists
today call Galician-Portuguese or Mediaeval Galician or Old
Portuguese. This common ancestral language was spoken in the
territories of the mediaeval Kingdom of Galicia."