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.

A real language lies behind reconstructed Proto-Indo-European, just as a real language lies behind any dictionary. And that language is a guide to the thoughts, concerns, and material culture of real people who lived in a definite region between about 4500 and 2500 BCE.

Language replacement always is accompanied by revised self–perceptions, a restructuring of the cultural classifications within which the self is defined and reproduced. Negative evaluations associated with the dying language lead to a descending series of reclassifications by succeeding generations, until no one wants to speak like Grandpa any