西ゲルマン語群
The history of the devoicing phenomenon within the West Germanic languages is not entirely clear, but the discovery of a runic inscription from the early fifth century suggests that this terminal devoicing originated in Frankish. Of the old West Germanic languages, Old Dutch, a descendant of Frankish, is the earliest to show any kind of devoicing, and final devoicing also occurred in Frankish-influenced Old French.