Primitive Indo-European k, t, p, became first in Teutonic h, th, f, and appear without further change in old Teutonic, if the accent rested on the preceding syllable; but these sounds became voiced and produced g, d, b, if the accent was originally on a different syllable
A statement, propounded by the Danish philologist Karl Verner in 1875, which explains certain apparent exceptions to Grimm's law by the original position of the accent