Origin: Celtic

Borrowed from French Gaule (“Gaul”), from Middle French Gaule (“Gaul”), from Old French Gaule, Waulle (“Gaul”, a term used to translate unrelated Latin Gallia (“Gaul”)), from Frankish *Walha(land) (“Gaul, Land of the Romans, foreigners”), from Proto-West Germanic *walh (“foreigner, Roman, Celt”), from Proto-Germanic *walhaz (“an outlander, foreigner, Celt”), probably of Celtic origin, from the same source as Latin Volcae (name of a Celtic tribe in South Germany, which later emigrated to Gaul). Akin to Old High German Walh, Walah (“a Celt, Roman, Gaul”), Old English wealh (“a non-Germanic foreigner, Celt/Briton/Welshman”), Old Norse Valir (“Gauls, Frenchmen”). More at Wales/Welsh, Cornwall, Walloon, and Vlach/Wallachia. Despite their similar appearance, Latin Gallia is not the origin of French Gaule. During the evolution from Latin to French, stressed initial /ˈɡa-/ yielded /dʒa/ > /ʒa/ (cf. Latin gamba > French jambe), while unstressed final /-lia/ yielded /ʎə/ > /j/ (cf. Latin filia > French fille). Thus, the regular outcome of Latin Gallia is /ʒaj/ ⟨Jaille⟩, which is attested in several French toponyms: La Jaille-Yvon, Saint-Mars-la-Jaille, etc.

Etymology: Wiktionary (CC-BY-SA)