Environmental conditions do not predict diversification rates in the Bantu languages

Beyer, R., Singarayer, J. S., Stock, J. T. and Manica, A. (2019) Environmental conditions do not predict diversification rates in the Bantu languages. Heliyon, 5 (10). e02630. ISSN 24058440 doi: 10.1016/j.heliyon.2019.e02630

Abstract/Summary

The global distribution of language diversity mirrors that of several variables related to ecosystem productivity. It has been argued that this is driven by the size of social networks, which tend to be larger in harsher climates to ensure food security, leading to reduced language divergence. Is this pattern purely synchronic, or is there also a quantifiable relationship between environmental conditions and language diversification over time? We used a spatio-temporal phylogeny of the Bantu language family to estimate local diversification rates at the times and locations of language divergence. We compared these data against spatially-explicit reconstructions of several palaeoclimate and palaeovegetation variables (mean annual temperature and the temperature of the coldest and warmest quarter, annual precipitation and the precipitation of the wettest and driest quarter, growing degree days, the length of the growing season, and net primary production), to investigate a potential link between local environmental factors and diversification rates in the Bantu languages. A regression analysis does not suggest a statistically significant relationship between climatic or ecological variables and linguistic diversification over time. We find a strong positive correlation between pairwise linguistic and geographic distances in the Bantu languages, arguing for a dominant role of isolation as a result of the rapid Bantu expansion that might have overwhelmed any potential influence of local environmental factors.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/86881
Identification Number/DOI	10.1016/j.heliyon.2019.e02630
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Elsevier
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