Alwin Kloekhorst Evidence for a new pre-Proto-Indo-European sound law *-ē ̆ m > PIE *-ō ̆ m Abstract: Several PIE forms with a word-final sequence *-ō ̆ m would be morphologi- cally better understandable if they ended in *-ē ̆ m. It is therefore proposed that, in its prehistory, Proto-Indo-European underwent a sound law *-ē ̆ m >*-ō ̆ m. 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. Keywords: Indo-European, phonology, sound change 1 Introduction In this article, it will be argued that, in its recent prehistory, Proto-Indo-European underwent a sound law *-ē ̆ m >*-ō ̆ m, i.e. a coloring of pre-PIE *ē ̆ to PIE *ō ̆ when standing before a word-final *-m. To my mind, this sound law would explain several PIE forms ending in *-ō ̆ m that are thus far unexplained (see §§2–4). Moreover, there are no serious counterexamples to it (see §5). After a discussion of a few possible additional examples in favor of this sound law (§6), I will come to conclusions (§7) and will subsequently say something about its relative chronology (§8) and typolog- ical parallels (§9). But let us first discuss the Proto-Indo-European lexemes that, in my view, have undergone this new sound law. 2*dʰǵṓm ‘earth (loc.sg.)’ The Hittite paradigm for ‘earth’ is generally reconstructed as in (1). 1 1 Note that this word is usually reconstructed *dʰeǵʰ-em-, with *ǵ h , but see Kloekhorst 2014b: 61–63 for arguments that indicate that the velar stop was not a media aspirata *ǵ h , but rather a media *ǵ, i.e. *dʰeǵ-em-. Alwin Kloekhorst, Leiden University; A.Kloekhorst@hum.leidenuniv.nl https://doi.org/10.1515/if-2024-0008 Open Access. © 2024 The Author(s), published by De Gruyter. This work is licensed under the Creative Commons Attribution 4.0 International License.