ABSTRACT
The vast interior of Eurasia is a linguistic spread zone-a genetic and typological bottleneck where many genetic lines go extinct, structural types tend to converge, a single language or language family spreads out over a broad territorial range, and one language family replaces another over a large range every few millennia.1 The linguistic geography of the central and western grasslands, from at least the Neolithic until early modern times, has consisted of an overall westward trajectory of language spreads and three more specific trajectories leading through the forest from the middle Volga to the Baltic Sea coast, across the steppe to the Danube plain, and across the desert south of the Caspian Sea to the Near East and Anatolia. Meanwhile, loanwords and cultural influence moved far out in all directions from the urban centres, beginning with ancient Mesopotamia, and these loanword trajectories are independent of language spread trajectories and sometimes move in the opposite direction. The wide linguistic ranges, westward trajectories of languages, and mechanisms of language spread in central Eurasia-as well as the nature of spread zones in general-are described in Volume II.
