The time and place of origin of South Caucasian languages

[RCO]

The time and place of origin of South Caucasian languages: insights into past human societies, ecosystems and human population genetics 
Article Open access Published: 30 November 2023
AlexanderGavashelishvili1*, Merab Chukhua2 , Kakhi Sakhltkhutsishvili3 , Dilek Koptekin4 & Mehmet Somel4

Scientifc Reports | (2023) 13:21133 | https://doi.org/10.1038/s41598-023-45500-w

  This study re-examines the linguistic phylogeny of the South Caucasian linguistic family (aka the Kartvelian linguistic family) and attempts to identify its Urheimat. We apply Bayesian phylogenetics to infer a dated phylogeny of the South Caucasian languages. We infer the Urheimat and the reasons for the split of the Kartvelian languages by taking into consideration (1) the past distribution ranges of wildlife elements whose names can be traced back to proto-Kartvelian roots, (2) the distribution ranges of past cultures and (3) the genetic variations of past and extant human populations. Our best-ft Bayesian phylogenetic model is in agreement with the widely accepted topology suggested by previous studies. However, in contrast to these studies, our model suggests earlier mean split dates, according to which the divergence between Svan and Karto-Zan occurred in the early Copper Age, while Georgian and Zan diverged in the early Iron Age. The split of Zan into Megrelian and Laz is widely attributed to the spread of Georgian and/or Georgian speakers in the seventh-eighth centuries CE. Our analyses place the Kartvelian Urheimat in an area that largely intersects the Colchis glacial refugium in the South Caucasus. The divergence of Kartvelian languages is strongly associated with diferences in the rate of technological expansions in relation to landscape heterogeneity, as well as the emergence of state-run communities. Neolithic societies could not colonize dense forests, whereas Copper Age societies made limited progress in this regard, but not to the same degree of success achieved by Bronze and Iron Age societies. The paper also discusses the importance of glacial refugia in laying the foundation for linguistic families and where Indo-European languages might have originated.

  The actual homeland of Indo-European languages has long been a mystery. Our fndings may contribute signifcantly to narrowing down the search area for this homeland. Linguistic and population genetic studies point towards south of the Caucasus as the inferred location4,8, 24,80. Glacial refugia, where human populations sought shelter during the last glacial period, are believed to have signifcantly infuenced the evolution and distribution of not only genetic but also linguistic diversity72. Glacial refugia appear to have a strong impact on linguistic family level diferences prior to the Copper Age in our study area. Genetic and linguistic evidence suggests that the spread of Hattic and Hurrian languages are associated with ancient Anatolians and Levantines, respectively24,81. Te geography of these ancient populations are strongly associated with the refugia, specifcally the Anatolian and Levantine refugia71. Te current study also suggests the importance of glacial refugia. Our analyses place the Kartvelian homeland in an area that intersects the Colchis glacial refugium in the South Caucasus. If refugia truly are sources of linguistic families and Indo-European languages originated somewhere south of the Caucasus, then the homeland of Indo-European languages can be refned to the Zagros or Hyrcanian (Alborz) refugia (Supplementary Fig. S4). Tese refugia are geographically closest to the South Caucasus71,72. Te proposition of placing the Indo-European homeland in the Zagros and/or Hyrcanian refugia sheds light on the structural relationships or prolonged contacts between Kartvelian and Indo-European languages4,8

 

https://www.nature.com/articles/s41598-023-45500-w