The location of the Anatolian branch of IE (Hittite and its sisters) is a problem, or at least a puzzle, for IE homeland studies. The Anatolian langu… - Johanna Nichols

Along the forest trajectory as well there is evidence of either an early Indie presence or undifferentiated Proto-Indo-Iranian or Proto-Indo-Aryan. Among the Indo-Iranian loans into early Finno-Ugric are some so phonologically archaic that they could well be Proto-Indo-Iranian... Iranian, but not Indo-Aryan, regularly reflects PIE s as h, so this Finno-Ugric form looks more Indie than Iranian. Abaev also cites some less well attested forms that could be specifically Indie... These borrowings would have taken place somewhere in the vicinity of the southern Ural Mountains. They were received from a steppe language and incorporated into Finno-Ugric as it began its spread along the forest trajectory. This linguistic evidence for an Indie or Proto-Indo-Iranian wave preceding Iranian on the steppe is weak but legitimate. In partial confirmation of it, Kuz’mina identifies the Andronovo culture of eastern Kazakhstan in the mid-second millennium BC as Indo-Aryan..... There is also evidence for Indo-Aryan along the steppe trajectory in the form of a set of Crimean place names which Trubač identifies as Indo-Aryan. This evidence is even weaker—place names in general have poor diagnostic value since they lack denotational meaning—but carefully researched and again legitimate. If Trubačv is right there is evidence for an Indie advance to the western steppe. Taken together, the Finno-Ugric and Crimean evidence are consistent with the assumption of a short-lived Indie or Indo-Aryan presence at the frontier of the Iranian spread on the steppe, in addition to the well-known Indie frontier in northeastern Mesopotamia and India.

A consequence of the reconstruction offered here is that the attested distribution of IE then turns out to be no singularity but just one regular episode in a standing pattern of spreads.

No migrations are required to derive the attested IE distribution from a reconstructed homeland consisting of a locus in western central Asia and a range over the steppe and desert. Sometime in the fourth to early third millennium, PIE spread along the steppe and southern trajectories to occupy the entire reconstructed range: the steppe, the desert of wester central Asia, part of the adjacent mountains, and perhaps some of south- west Asia. At this time its distribution was continuous, and that distribution had been achieved not by migration but by expansion.