Gaulish was the language of Gaul, before and at the time of the Roman conquest. It derives from the Celtic branch of the Indo-European family of languages and was spoken until the 4th century AD, although it may have lived longer.
Until recently, some have claimed that the Breton language is the modern continuation of the Gaulish language (in particular the Vannetais dialect), but this view is no longer widely accepted, because it has been found that Breton is directly coming from Brythonic imported from British Isles and has only a very slight influence of Gaulish.
Although it is only known from glosses and a few inscriptions, some believe it was sufficiently close to Brythonic to consider them a single language separated only by dialectal differences. Although much is still debated, it would tend to indicate that Gaulish was a "P" CelticLanguage.
On many issues Gaulish was seemingly similar to LatinLanguage, in particular for the declensions and it may have helped it to disappear.
Thus, when the Germanic tribes poured over the Western part of the Roman Empire in the 5th century they brought their GermanicLanguage dialects with them. However, at that time, Gaulish had almost completely disappeared and had already been replaced by various dialects of the vulgar latin, which would eventually evolve into the "Romance" subfamily of languages. And as the Germanic tribes were relatively few in numbers, they became quickly assimilated, leaving only a few loanwords on the local idioms. This explains why the current FrenchLanguage originates from vulgar Latin with a clear Germanic influence, rather than Gaulish itself.
Only a very few words in the modern FrenchLanguage can be traced back to Gaulish origins