Indo-Hittite in the context of "Proto-Indo-European Urheimat hypotheses"

The Proto-Indo-European homeland was the prehistoric homeland of the Proto-Indo-European language (PIE), meaning it was the region where the proto-language was spoken before it split into the dialects from which the earliest Indo-European language later evolved.

The most widely accepted proposal about the location of the Proto-Indo-European homeland was called the steppe hypothesis. It puts the archaic, early, and late PIE homeland in the Pontic–Caspian steppe around 4000 BCE. A notable second possibility, which has gained renewed attention during the 2010s and 2020s due to aDNA research, is the Armenian hypothesis, which situates the homeland for archaic PIE ('Indo-Hittite') south of the Caucasus mountains. A third contender is the Anatolian hypothesis, which puts it in Anatolia c. 8000 BCE. Several other explanations have been proposed, including the outdated but historically prominent North European hypothesis, the Neolithic creolisation hypothesis, the Paleolithic continuity paradigm, the Arctic theory, and the "indigenous Aryans" (or "out of India") hypothesis. These are not widely accepted, and are considered to be fringe theories.

The Armenian hypothesis, also known as the Near Eastern model, is a theory of the Proto-Indo-European homeland, initially proposed by linguists Tamaz V. Gamkrelidze and Vyacheslav Ivanov in the early 1980s, which suggests that the Proto-Indo-European language was spoken during the 5th–4th millennia BC in "eastern Anatolia, the southern Caucasus, and northern Mesopotamia".

Recent ancient DNA research has led to renewed suggestions of a Caucasian homeland for a "pre-proto-Indo-European". Particularly, an admixture between the Khvalynsk and Caucasian Copper Age burials gave rise to the ancestry that later became known as a typical marker (WSH – Western Steppe Herders) of the Yamnaya pastoralists. It also lends support to the Indo-Hittite hypothesis, according to which both proto-Anatolian and proto-Indo-European split off from a common mother language "no later than the 4th millennium BCE".These suggestions have been disputed in other recent research, which still locates the origin of the ancestor of proto-Indo-European in the Eastern European/Eurasian steppe or from a hybridization of both steppe and Northwest-Caucasian languages. The origin of the Anatolian languages according to the Near Eastern model has also been challenged because "[a]mong comparative linguists, a Balkan route for the introduction of Anatolian IE is generally considered more likely than a passage through the Caucasus, due to, for example, greater Anatolian IE presence and language diversity in the west."