Proto-Indo-Iranian follows: The Satem shift, consisting of two sets of related changes. The PIE palatals *ḱ *ǵ *ǵʰ are fronted or affricated, eventually resulting in PII *ć, *ȷ́, *ȷ́ʰ, while the PIE labiovelars *kʷ *gʷ *gʷʰ merge with the velars *k *g *gʰ. The PIE liquids merge as . The PIE syllabic nasals merge with . Bartholomae's law: an aspirate immediately followed by a voiceless consonant becomes voiced stop + voiced aspirate. In addition, dʰ + t > dᶻdʰ. The Ruki rule: *s is retracted to *š when immediately following a liquid (*r *r̥ *l *l̥), a high vowel (*i *u), a PIE velar (*ḱ *ǵ *ǵʰ *k *g *gʰ *kʷ *gʷ *gʷʰ) or the syllabic laryngeal *H̥. Its allophone *z likewise becomes *ž. Before a dental occlusive, *ĉ becomes *š and *ĵ becomes *ž. *ĵʰ also becomes *ž, with aspiration of the occlusive. The sequence *ĉš was simplified to *šš. The "second palatalization" or "law of palatals": *k *g *gʰ develop palatal allophones *č *ǰ *ǰʰ before the front vowels *i, *e. through an intermediate *kʲ *gʲ *gʲʰ. Brugmann's law: *o in an open syllable lengthens to *ō. The vowels *e *o merge with *a. Similarly, *ē, *ō merge with *ā. This has the effect of giving full phonemic status to the second palatal series *č *ǰ *ǰʰ. In certain positions, laryngeals were vocalized to *i. This preceded the second palatalization. Following a consonant, and preceding a consonant cluster Following a consonant and word-final The Indo-European laryngeals all merged into one phoneme *H, which may have been a glottal stop. This was probably contemporary with the merging of *e and *o with *a. According to Lubotsky's Law, *H disappeared when followed by a voiced nonaspirated stop and another consonant: Subsequent sound changes Among the sound changes from Proto-Indo-Iranian to Indo-Aryan is the loss of the voiced sibilant *z; among those to Proto-Iranian is the de-aspiration of the PIE voiced aspirates. Morphology Proto-Indo-Iranian has preserved much of the morphology of Proto-Indo-European: thematic and athematic inflection in both nouns and verbs, all three numbers of singular, dual and plural, all the tense, mood and voice categories in the verb, and the cases in the noun. An important innovation in the noun is the creation of a genitive plural ending *-nām used with vowel stems. In verbs, the chief innovation is the creation of a passive conjugation with the suffix *-yá, with