[3] *Walhaz is a loanword derived from the name of the Celtic tribe which was known to the Romans as Volcae (in the writings of Julius Caesar) and to the Greeks as Οὐόλκαι Ouólkai (Strabo and Ptolemy).[2][5] The Volcae tribe occupied territory neighbouring that of the Germanic people and seem to have been referred to by the proto-Germanic name *Walhaz (plural *Walhōz, adjectival form *walhiska-).Subsequently, this term *Walhōz was applied rather indiscriminately to the southern neighbours of the Germanic people, as evidenced in geographic names such as Walchgau and Walchensee in Bavaria[3] or Walensee in Switzerland.[1] In Old English, *:walhaz developed into wealh, retaining the inherited meaning ‘a foreigner, more particularly a pre-Anglo-Saxon inhabitant of Britain who spoke Celtic or Latin or both’.The old feminine derivative of *walhaz, Old English wiln < *wielen < * wealh-in-, even exclusively means ‘a female slave’ and is likewise concentrated in the Saxon south of England.
Map of Walhaz-derived exonym variants for Romance speakers