Sir Colin Renfrew
Andrew Colin Renfrew, Baron Renfrew of Kaimsthorn (born 25 July 1937) is a British archaeologist, paleolinguist and Conservative peer noted for his work on radiocarbon dating, the prehistory of languages, archaeogenetics, and the prevention of looting at archaeological sites.
This area [east Macedonia], although firmly now part of Greece, has sometimes been a marginal one, and may at times have owed allegiance in different directions through a process of boundary displacement. It was indeed occupied in early classical times by Thracian tribes, barbarians who did not speak the Greek language. No doubt they did indeed speak a Thracian language akin to that in what is now Bulgaria, whose origins were suggested earlier.
Renfrew, Colin. Archaeology and Language: The Puzzle of Indo-European Origins, Penguin books 1990, p. 176