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

[ph2ter]

It seems to me very unlikely:

[jdean]

Was going to post about this paper today so pleased to see it already here.

I'm no linguist but this raised a red flag for me too, the fact they are relying on two linguistic papers that are both a 1/4 of a century old and Lazaridis' DNA paper (which has had a very mixed reception) for confirmation doesn't exactly fill me with confidence.

OOI How well considered is Bayesian phylogenetics in the linguistic community ?

[jdean]

BTW this is Johanna Nichols thoughts on the Caucasian Substrate Hypothesis, which is amusing as she's often credit as a supporter : )

Comments on Alan Bomhard

[Jaska]

jdean:

“OOI How well considered is Bayesian phylogenetics in the linguistic community?”

The method gives out what is put in. The main weakness is that the number of shared words does not automatically translate to the taxonomic model (“family tree”) of a language family, because there are other possible reasons why some branches share more or less words with other branches. These other possible explanations are normally just ignored in the “phylolinguistic” framework. 
https://journal.fi/fuf/article/view/85674/44638

This weakness is of course carried to the dating, as well. The achieved high age of a proto-language can actually be a direct consequence of one branch replacing a large amount of its vocabulary, which is then interpreted so that the gap between it and the other branches is erroneously deep and the language family therefore gets an erroneously early dating.

As a dating method, it is not as reliable as paleo- or archaeo-linguistic dating, when the latter are based on solid evidence (of course, there are occasionally also weaker correlations of this type).

The study:

“The actual homeland of Indo-European languages has long been a mystery. Our findings may contribute significantly to narrowing down the search area for this homeland. Linguistic and population genetic studies point towards south of the Caucasus as the inferred location.”

They refer only to rather selected sources, of recent ones only to Heggarty et al. 2023 and Lazaridis et al. 2022. The Indo-Anatolian proto-language (Early Proto-Indo-European) is not as easy to locate as Late Proto-Indo-European, and it is not at all certain that the language was spoken to the south from the Caucasus. Language does not always follow the major genetic root, and even though the Caucasus ancestry connects the steppe and Anatolia, it could be connected also to many other language families, not necessarily Indo-Anatolian. Languages have replaced earlier languages everywhere many times over, and we cannot just decide that Indo-Anatolian was connected to the spread of the Caucasus ancestry.

About the refugia: Why should the connections between Indo-European and Kartvelian be so ancient? A couple of millennia before the Indo-European expansion would be enough for their contacts. There was still more than 10 000 years from that to the last glacial maximum, so nobody can even reliably guess where so distant ancestor of Indo-European was spoken. It is very possible that it was spoken nowhere near the Caucasus at that time.

To conclude, Gavashelishvili et al. build assumptions upon assumptions.

[jdean]

The method gives out what is put in. The main weakness is that the number of shared words does not automatically translate to the taxonomic model (“family tree”) of a language family, because there are other possible reasons why some branches share more or less words with other branches. These other possible explanations are normally just ignored in the “phylolinguistic” framework. 
https://journal.fi/fuf/article/view/85674/44638

Isn't this  Russell Gray's favoured methodology, and historical linguists thoughts on his papers are well known : )

[Psynome]

Putting the PIE section aside because at this point it's not worth commenting on, I'll say the authors got the Proto-Kartvelian history partially correct but with some major issues.

The Colchis and Chorokhi (Coruh) regions are the best candidates for the Proto-Kartvelian homeland. That much is true. But the early split date and the reasoning given by the authors for it is very questionable. They try to attribute the divergence of Svan and Karto-Zan to Karto-Zan becoming agriculturalists and Svan remaining foragers starting around 8000bp, coinciding with the arrival of Anatolian farmer ancestry in the Western Caucasus.

But this scenario is at odds with the farming language dispersal hypothesis, which in its mass population movement form now has enough support from ancient genomics to be a strong prior assumption. We are left wondering why the Neolithic communities decided to retain a forager language despite their massive admixture and shifts in lifestyle, comparable to those experienced in Europe where forager languages were replaced. What's more, the authors attempt to place early Kartvelian speakers in Eastern Georgia, when the genetic, linguistic, and historical evidence shows that this region was most likely earlier inhabited by Nakh groups that were assimilated into an expanding Georgian culture from the west well after the Neolithic period. The scenario of a more recent arrival in Eastern Georgia explains why the diversity of Kartvelian is greatest in the west.

I believe that the best place to look for a Proto-Kartvelian unity is in the Bronze to Iron Age Colchian culture in its early stages around 4.5kya. This pushes the time of breakup to a more realistic date and neatly places the proto language community into a single archaeological culture rather than attempting to, for example, place Karto-Laz into Neolithic communities in the separate Chorokhi and Mtkvari watersheds while forager Svan sits awkwardly between them.

[vasil]

It seems to me very unlikely:

I am going to go look for this paper but even before I do I call absolute bull on this map.

[vasil]

https://www.researchgate.net/publication...he_Ice_Age

[vasil]

I have breaking news guys the Mammoth steppe was apparently a desert and ANE>EHG is a hoax.
https://onlinelibrary.wiley.com/doi/epdf.../geb.12437

[vasil]

BTW MA-1 is dated 24000bp and Villabruna 1 is dated 14000bp so the expansion of ANE into the Pontic steppe happened smack dab in the middle of the LGM ie the Pontic steppe was inhabited for sure. Also Kostenki-12 is 30000 years old which then got replaced by EHG so I dont know if I would exactly call it a refugium but there was definitely continuous ocupation before, during and after the LGM.