The main claims of Bomhard's paper are that PIE originated in Central Asia, which accounts for its Eurasiatic properties such as resemblant pronouns (Uralic, IE, Kartvelian, Turkic, Mongolic, Tungusic) and originally agglutinating morphology; then it moved by migration to the western steppe, where profound influence of a North Caucasian language or languages (chiefly West Caucasian) reshaped its sound system, aspects of its morphology, and its lexicon. The work is carefully done, with a large and systematic lexical survey, consideration of archaeological evidence, attention to evidence of contacts and migration, and extensive bibliography. PIE does indeed seem to have a curious typological mix of southwestern and north-central Eurasian traits. I have questions, however, about aspects of the linguistic geography, the Caucasian contacts, and the number and type of lexical resemblances
