Perhaps the usual reflex was "*b" (as suggested by the connection of "bid" < "*bidjaną" and Old Irish "guidid"), but "*w" appears in certain cases (possibly through dissimilation when another labial consonant followed?), such as in "warm" and "wife" (provided that the proposed explanations are correct). Proto-Germanic "*hw" voiced by Verner's law fell together with this sound and developed identically, compare the words for 'she-wolf': from Middle High German "wülbe" and Old Norse "ylgr", one can reconstruct Proto-Germanic nominative singular "*wulbī", genitive singular "*wulgijōz", from earlier "*wulgwī", "*wulgwijōz".