The English term "a winter" matches the Gaulish term "giam"

Inscriptions
The longest inscription is the Coligny calendar found in eastern France in 1897. It is preserved in two bronze tablets. It’s a lunar calendar with months that are 29 days long. Other inscriptions could be found on coins, memorials, and dedications to gods.
Similarities with Latin
Gaulish is similar to Latin in terms of the way that some words are structured. But there are some words for which there is no equal in Latin because they were not necessarily common in Rome. Examples include “sapo” or “soap”, “cervesia” or beer, and “ tunna” or “barrel” Despite some differences in vocabulary, Gaulish language’s similarities to Latin contributed to its disappearance as a language.
French Gaulish
French is based on Frankish and Latin but it could have very well been based on Gaulish too. Had Latin been a much harder language for Gauls to learn, they could have influenced this romance language. But Gaul became overrun by Germanic Franks during the late Empire and by then Gaulish was on its way out as a language.