walhaz > walh > wealh > Wēalas > Wales walhaz > walh > wealh > (+Körnɨw) Wēalas > Cornwall walhaz > walh > Wallon > Walloon > Wallonia walhaz > walhs > valxu > volxъ > volox > Walache > valah > Valahia > Wallachia
Words For Granted has an episode about Wales and its etymology. Tldr: It goes back to Proto Germanic and meant "foreign" (originally for Romance languages, later everything they didn't understand). Hence also the German "Kauderwelsch" which basically means unintelligible gibberish