Aquitanian and its related descendant, Basque, are commonly thought to be Pre-Indo-European languages, a remnant of the languages spoken in Western Europe before the arrival of Indo-European speakers. It may be possible to trace the Aquitanians more or less directly back to the Chalcolithicculture of Artenac, but the age of the Aquitanian language, and of the Basque language, is uncertain. Some contend that Basque dates to the age of metal; others, claiming the derivation of words for "knife", "ax" and "hoe" from the word for "stone", conclude that the language dates to the Stone Age or Neolithic period, when those tools were made of stone. This derivation, however, has been called into question: see the aizkora controversy.
Persons' names and gods' names
Almost all of the Aquitanian inscriptions that have been found north of the Pyrenees are in the territory that Greek and Roman sources assigned to Aquitanians.
Most Aquitanian onomastic elements are clearly identifiable from a Basque perspective, matching closely the forms reconstructed by the vascologist Koldo Mitxelena for Proto-Basque:
The vascologist Joaquín Gorrochategui, who has written several works on Aquitanian, and Mitxelena have pointed out the similarities of some Iberian onomastic elements with Aquitanian. In particular, Mitxelena spoke about an onomastic pool from which both Aquitanian and Iberian would have drawn:
Since ancient times there have been indications of a relationship between present Southwestern France and the Basques. During the Roman conquest of Gaul by Julius Caesar, Aquitania was the territory between the Garonne and the Pyrenees. It was inhabited by tribes of horsemen who Caesar said were very distinct in customs and language from the Celts of Gaul. During the Middle Ages, this territory was named Gascony, derived from Vasconia and cognate with the word Basque. There are many clues that indicate that Aquitanian was spoken in the Pyrenees at least as far east as Val d'Aran. Place-names that end in ‑os, ‑osse, ‑ons, ‑ost and ‑oz are considered to be of Aquitanian origin, such as the place-name Biscarrosse, which is directly related to the city ofBiscarrués south of the Pyrenees. "Biscar" means "ridge-line". Such suffixes in place-names are ubiquitous in the east of Navarre and in Aragon, with the classical medieval ‑os > ‑ues occurring in stressed syllables, pointing to a language continuum on both sides of the Pyrenees. This strong formal element can be traced on either side of the mountain range as far west as an imaginary line roughly stretching from Pamplona to Bayonne, where it ceases to appear. Other than place-names and a little written evidence, the picture is not very clear in the west of the Basque Country, as the historical record is scant. The territory was inhabited by the Caristii, Varduli, and Autrigones, and has been claimed as either Basque or Celtic depending on the author, since Indo-European lexical elements have been found underlying or intertwined in the names given to natural features, such as rivers or mountains in an otherwise generally Basque linguistic landscape, or Spanish, especially in Álava. Archaeological findings in Iruña-Veleia in 2006 were initially claimed as evidence of the antiquity of Basque in the south but were subsequently dismissed as a forgery. The Cantabrians are also mentioned as relatives or allies of the Aquitanians: they sent troops to fight on their side against the Romans. The Vascones who occupied modern Navarra are usually identified with the Basques, their name being one of the most important pieces of evidence. In 1960, a stele with Aquitanian names was found in Lerga, which could reinforce the idea that Basques and Aquitanians were related. The ethnic and linguistic kinship is confirmed by Julio Caro Baroja, who considers the Aquitanian-Basque relationship an ancient and medieval stage ahead of the well-attested territorial shrinking process undergone by the Basque language during the Modern Age.