Evidence for a new pre-Proto-Indo-European sound law *-ēm > PIE *-ōm

Abstract Several PIE forms with a word-final sequence *-ō̆m would be morphologically better understandable if they ended in *-ē̆m. It is therefore proposed that, in its prehistory, Proto-Indo-European underwent a sound law *-ē̆m > *-ō̆m. This article will treat the relevant evidence in favor of this new sound law, as well as discuss an apparent counterexample. Moreover, it will offer some typological parallels for this development.