*Walhaz is a reconstructed Proto-Germanic word meaning 'foreigner', or more specifically 'Roman', 'Romance-speaker' or '(romanized) Celt', and survives in the English words of 'Wales/Welsh' and 'Cornwall.' The term was used by the ancient Germanic peoples to describe inhabitants of the former Roman Empire, who were largely romanised and spoke Latin languages (cf. Valland in Old Norse). The adjectival form is attested in Old Norse valskr, meaning 'French'; Old High German walhisc, meaning 'Romance'; New High German welsch, used in Switzerland and South Tyrol for Romance speakers; Dutch Waals 'Walloon'; Old English welisċ, wælisċ, wilisċ, meaning 'Brythonic'. The forms of these words imply that they are descended from a Proto-Germanic form *walhiska-.

From *Walhaz to welsch

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’. It also came to imply the 'social position of the British natives that in the West Saxon dialect of Old English' came to mean ‘(British) slave’. 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.

From *Walhaz to Vlach

From the Germanic and Slavic peoples the term passed to other groups, such as the Hungarians (oláh, referring to Vlachs, generally used for Romanians; olasz, referring to Italians), Turks (Ulahlar) and Byzantines (Βλάχοι Vláhi) and was used for all Latin people of the Balkans.