Gascon language
Gascon (Occitan: [ɡasˈku], French: [ɡaskɔ̃]) is a dialect of Occitan. It is mostly spoken in Gascony and Béarn in southwestern France (in parts of the following French départements: Pyrénées-Atlantiques, Hautes-Pyrénées, Landes, Gers, Gironde, Lot-et-Garonne, Haute-Garonne, and Ariège) and in the Aran Valley of Catalonia. It has about 250,000 speakers worldwide.
Only Aranese, a southern Gascon variety, is spoken in Catalonia. Aranese has been greatly influenced recently by Catalan and Spanish. Both these influences tend to differentiate it more and more from the dialects of Gascon spoken in France. Since the 2006 adoption of the new statute of Catalonia, Aranese is co-official with Catalan and Spanish in Catalonia (before, this status was valid for the Aran Valley only).
Linguistic classification
See Occitan: Debates concerning linguistic classification.
Basque substrate
The language spoken in Gascony before Roman rule was part of the Basque dialectal continuum (see Aquitanian language); the fact that the word 'Gascon' comes from the Latin root vasco/vasconem, which is the same root that gives us 'Basque', implies that the speakers identified themselves at some point as Basque. There is a proven Basque substrate in the development of Gascon. This explains some of the major differences that exist between Gascon and other Occitan dialects.