Short answers, pulled from the story.
No text written in the Aquitanian language has survived to the modern era. The only evidence comes from onomastic data found within Latin inscriptions created during the Roman imperial period. Roughly 200 personal names and about 60 deity names have been preserved indirectly through these stone records.
Joaquín Gorrochategui concludes the tongue was spoken from at least the 1st century BC until the end of the Roman Empire. These inscriptions date primarily between the 1st and 3rd centuries AD, with a few possibly extending into the 4th or 5th centuries.
Scholars generally agree that Aquitanian was genetically related to the modern Basque language. Some experts like R. L. Trask argue it served as a near-direct ancestor to today's speakers while others including Lyle Campbell suggest it may be a close relative instead of a direct parent.
The Aquitanian language spread across a vast region stretching from Biscay in the west to the Aran Valley in the east. It covered territory from the Aquitanian Plain down to the Ebro river and extended south into Navarre and Castile.
Scholars rely entirely on these scattered names to reconstruct any understanding of the tongue because no books or official documents have survived. The absence of full sentences leaves linguists with fragments rather than complete texts to analyze.