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.

Three language trajectories are shown.., and these are contemporaneous but not equal in prominence or carrying power. The central one, henceforth the steppe trajectory, shows the east-to-west spread of languages across the Eurasian steppe, and is based on four spreads: that of IE to Europe in the Bronze Age, that of Iranian to (and occasionally into) Central Europe during the Iron Age, that of Turkic in the early centuries of this era, and that of Mongolian beginning in the Middle Ages. To the north of it is the almost equally extensive forest trajectory through the northern forests. This is the route followed by the Uralic language family in its spread from the central Urals (c. the fourth or fifth millennium) as far west as Norway and Estonia (by perhaps the first millennium BC). To the south of the Caspian and Black Seas runs the southern or desert trajectory that brought the Mongols to the southern Caucasus, and before that Turkish to Turkey, and before that Iranian languages to ancient Persia and northern Mesopotamia, and still earlier Armenian, Hittite and its sisters, and other early IE dialects to Asia Minor.

Approximately every two millennia, then, there has occurred a spread of a language family from a locus in the eastern part of the central Eurasian spread zone to cover the steppe and central Asia, extending partially or intermittently to the Danube plain, Anatolia, and northern Mesopotamia. The loci of the historically attested spreads are near the edge of the spread zone rather than in the centre of it: the piedmont to the south (Bactria-Sogdiana) for Iranian, the north of Mongolia for Turkic and Mongolian. The trajectories of language spread run east to west along the steppe and through the desert to the Near East as shown .... To take clear and historically well-attested examples, the locus, trajectories, and range of IE must have been much like those of Iranian or Turkic. ... The placement of the locus specifically in the vicinity of Bactria-Sogdiana is justified in .... A homeland reconstructed as locus, trajectory and range removes the dilemma: a locus in the vicinity of Bactria-Sogdiana implies a spread beginning at the frontier of ancient Near Eastern civilization and a range throughout the steppe and central Asia, following the east-to-west trajectory, with occasional or periodic spreads into the Danube plain and Anatolia.