- Lexical borrowing between PIE and Kartvelian/Semitic languages places the early PIE homeland in the Near East
- The maximum dialectal diversity within IE in the Balkans places the secondary PIE homeland in Southeastern Europe
My only point of disagreement with Dolgopolsky's model is that the secondary Balkan homeland was responsible only for the European IE languages (and Armenian) but not for the eastern migration of the Tocharians and Indo-Iranians.
I have argued elsewhere in my blog about the West Asian origin of these Asian IE branches; a Balkan origin for them seems unlikely at the moment, due to the lack of Y-haplogroup I and of the "Southern European" component among the eastern Indo-Europeans. Of course, we must wait to see what surprises archaeogenetics may have in store for us.