An inverse correlation between structural linguistic and human genetic diversity

Abstract

Linguistic structures show uneven global distributions, but it remains unknown to what extent such distributions are driven by human population history at a global scale. Here, we track population history through population genetics and show that, adjusting for geography, phylogeny, and environment, genetic diversity (in terms of local homozygosity modeled across individuals) is inversely correlated with linguistic diversity (in terms of local entropy of structural features modeled across languages). This inverse correlation arises from the parallel impact of isolation vs. contact on both genomic and structural linguistic diversity: Isolation leads to low genetic diversity and promotes structural linguistic diversification, while contact and migration yield higher genetic diversity and promote linguistic homogenization. The extent of the correlation varies across world regions and aspects of language, but its overall global robustness highlights how hotspots of linguistic diversity can serve as a compelling example of the flexibility of human language, since they have been less affected by the increase of contact and migration that occurred over recent millennia and homogenized linguistic structures.