Inferring Language Dispersal Patterns.

As Dmitry Pruss, who sent me the link, said, another computational not quite phylogenetic paper: Sizhe Yang, Xiaoru Sun, Li Jin, and Menghan Zhang, Inferring language dispersal patterns with velocity field estimation (Nature Communications 15, 190 [2024]). The abstract:

Reconstructing the spatial evolution of languages can deepen our understanding of the demic diffusion and cultural spread. However, the phylogeographic approach that is frequently used to infer language dispersal patterns has limitations, primarily because the phylogenetic tree cannot fully explain the language evolution induced by the horizontal contact among languages, such as borrowing and areal diffusion. Here, we introduce the language velocity field estimation, which does not rely on the phylogenetic tree, to infer language dispersal trajectories and centre. Its effectiveness and robustness are verified through both simulated and empirical validations. Using language velocity field estimation, we infer the dispersal patterns of four agricultural language families and groups, encompassing approximately 700 language samples. Our results show that the dispersal trajectories of these languages are primarily compatible with population movement routes inferred from ancient DNA and archaeological materials, and their dispersal centres are geographically proximate to ancient homelands of agricultural or Neolithic cultures. Our findings highlight that the agricultural languages dispersed alongside the demic diffusions and cultural spreads during the past 10,000 years. We expect that language velocity field estimation could aid the spatial analysis of language evolution and further branch out into the studies of demographic and cultural dynamics.

Thanks, Dmitry!


  1. cuchuflete says

    For those who might share my ignorance of some of the terms used, here’s
    demic diffusion
    according to wikipedia:

    “ Demic diffusion, as opposed to trans-cultural diffusion, is a demographic term referring to a migratory model, developed by Luigi Luca Cavalli-Sforza, of population diffusion into and across an area that had been previously uninhabited by that group and possibly but not necessarily displacing, replacing, or intermixing with an existing population (such as has been suggested for the spread of agriculture across Neolithic Europe and several other Landnahme events).

    An example of Demic diffusion: ancient European Neolithic farmers were genetically closest to ancient Near-Eastern/Anatolian populations. Genetic matrilineal distances between European Neolithic Linear Pottery Culture populations (5,500–4,900 calibrated BC) and modern Western Eurasian populations.[1]
    In its original formulation, the demic diffusion model includes three phases: (1) population growth, prompted by new available resources as in the case of early farmers, and/or other technological developments; (2) a dispersal into regions with lower population density; (3) a limited initial admixture[clarification needed] with the people encountered in the process.”

  2. David Eddyshaw says

    Interesting to see Bantu in there (an obvious choice for this sort of thing.)

    By chance (or perhaps Morphic Resonance) I was just reading something that suggested that the longstanding assumption/belief that agriculture drove the great Bantu expansion actually doesn’t match the archaeological evidence (such as it is) all that well (I can’t place it just now, unfortunately.)

    The linguistic evidence may be an artefact of the longstanding reluctance to deal with the implications of the fact that traditional proto-Bantu reconstructions tend to rely on explaining away the often very different Northwestern Bantu languages by conveniently unidentifiable mysterious substrates: this looks pretty unprincipled. The Northwestern languages are very much the most diverse group and they must surely be nearest the starting point of the whole migration, as we’ve known since Greenberg’s day, if not before; which is all exactly what you would therefore expect to see.

    The traditional doctrine about proto-Bantu, which assumes that you can just reconstruct proto-Bantu without paying any mind to the Northwest, may even turn out to be an intra-Bantu version of something I’ve often moaned about: the tendency to be so dazzled by the successes of reconstruction in comparative Bantu that people just assume that proto-Niger-Congo was pretty much the same as proto-Bantu. (I admit that it would please me to discover that even proto-Bantu wasn’t all that much like “proto-Bantu” really.)

    This may not undermine the paper so much: you’d just need to mentally substitute “the language groups now represented by the Eastern and Southern Bantu languages” for “Bantu”: that seems to be the part that underwent relatively recent relatively rapid expansion. I imagine that most of their data are from those parts anyway.

  3. they must surely be nearest the starting point of the whole migration, as we’ve known since Greenberg’s day, if not before

    The heuristic that diversity equals place of origin is due to Sapir, so far as I know. Or do you mean Bantu specifically?

  4. David Eddyshaw says

    Yeah, I meant that Greenberg was the one who was chiefly responsible for the fact of Bantu belonging genetically with West African languages becoming the received view (though he didn’t originate it.) It’s not unreasonable to explain the strangeness of NW Bantu as due to “contamination” by less-synthetic West African languages if (like Guthrie, even) you think that Bantu actually originated elsewhere.

    It is unreasonable now. The synthetic-good analytic-bad attitudes dating from the racism of some earlier Bantuists and nineteenth-century notions of language evolution cast their malignant shadow even now.

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