The Indo-European language spoken by the Indo-Iranians in the late 3rd millennium BC was a Satem language still not removed very far from the Proto-Indo-European language, and in turn only removed by a few centuries from Vedic Sanskrit of the Rigveda. The main phonological change separating Proto–Indo-Iranian from Proto–Indo-European is the collapse of the ablauting vowels "*e, *o, *a" into a single vowel, Proto–Indo-Iranian "*a" (but see Brugmann's law). Grassmann's law and Bartholomae's law were also complete in Proto–Indo-Iranian, as well as the loss of the labiovelars (kw, etc.) to k, and the Eastern Indo-European (Satem) shift from palatized k' to ć, as in Proto–Indo-European *k'ṃto- > Indo-Iran. *ćata- > Sanskrit śata-, Old Iran. sata
"100".

Among the sound changes from Proto–Indo-Iranian to Indo-Aryan is the loss of the voiced sibilant "*z", among those to Iranian is the de-aspiration of the PIE voiced aspirates.

Genetics
தோற்றம்
அனதோலியாவின் மித்தானி இராச்சியம்
Language