Proto-Indo-European contained roots that meant “sheep,” “ewe,” “ram,” and “lamb”—a developed vocabulary that undoubtedly indicates familiarity with domesticated sheep.

The possible homeland locations can be narrowed further by identifying the neighbors. The neighbors of the speakers of Proto-Indo-European can be identified through words and morphologies borrowed between Proto-Indo-European and other language families.

The other side of understanding language shift is to ask why the identities associated with Indo–European languages were emulated and admired. It cannot have been because of some essential quality or inner potential in Indo–European languages or people. Usually language shift flows in the direction of paramount prestige and power. Paramount status