An Etymological Dictionary of the German Language/wer

by Friedrich Kluge

wer, pron., ‘who,’ from MidHG. and OHG. wër (earlier hwër), interr. pron.; the nom. sing. preserves the r as a representative of old s; comp. Goth. hwas, ‘who,’ also AS. hwâ, E. who. The Teut. stem of the interr. pron. was hwa-, hwe-, from Aryan ko, ke, which is found in non-Teut. in Lat. quo-d, Gr. πότερος, (κότερος), Lith. and Sans. kas, ‘who.’ Hence wann, weder, welch, wenn, wie, and wo. Further details belong to grammar.