Thraco-Illyrian

Thraco-Illyrian is a hypothesis that the Thraco-Dacian and Illyrian languages comprise a distinct branch of Indo-European. Thraco-Illyrian is also used as a term merely implying a Thracian-Illyrian interference, mixture or sprachbund, or as a shorthand way of saying that it is not determined whether a subject is to be considered as pertaining to Thracian or Illyrian. Downgraded to a geo-linguistic concept, these languages are referred to as Paleo-Balkan.

The linguistical hypothesis was especially current in the early 20th century, but after the 1960s it was seriously called into question. New publications argued that no strong evidence for Thraco-Illyrian exists, and that the two language-areas show more differences than correspondences (Vladimir Georgiev, Ivan Duridanov, Eric Hamp, et al.).

Linguistic contact or common branch?

The rivers Vardar, South and Great Morava are generally taken as the rough line of demarcation between the Illyrian sphere on the west and Thracian on the east. There is however much interference in the area between Illyrian and Thracian, with Thracian groups inhabiting Illyrian lands (the Thracian Bryges for example) and Illyrian groups overlapping into the Thracian zone (the Dardani seem to be a Thraco-Illyrian mix; Wilkes, 1992 et al.). It appears that Thracian and Illyrian do not have a clear-cut frontier. Similarities found between the Illyrian and Thracian lexis can thus be seen as merely linguistic interference (Hemp, Georgiev et al.).