The magnificent Lexilogos site links to all manner of reference works involving language: family names, etymology, place names, slang, and much else, usually starting with French and continuing with a scattering of other languages. To give just one example, check out this online dictionary of French family names; here’s the etymology of De Gaulle (from the Dawance-Decroix page):
Apparemment, il s’agit de la francisation d’un nom flamand, De Walle, qui signifie sans doute le Wallon (= l’étranger, celui qui n’appartient pas au peuple germanique, du vieux-haut-allemand walah = étranger, également à l’origine des toponymes Gaule et Galles). A noter l’existence du patronyme Waulle dans le Pas-de-Calais. Autre possibilité : walle = mur, fossé.
(Via Carnet de Zénon.)
I’d like to see a thorough study of the various cognates Gaul, Galicia, Wallonia, Wales, Wallachia, etc. I’ve been told that all of them name foreign peoples “outside the walls” from a Roman perspective — the second explanation in your link.
This issue first came to my attention in the liner notes to an LP of Bartok’s musicological studies among the Vlachs, IIRC. Not exactly a solid source to refer to, but I love the guy who wrote it, whoever he was.
Thanks to Lexilogos, you can now produce text in Linear B! Not that anyone can read it: 𐀪𐀚𐀀𐀪𐀠. (Courtesy of Rémy Viredaz at FB.)