Disentangling complex language contact and admixture in the broad Gansu-Qinghai region

Language evolution in the Gansu-Qinghai (GQ) region provides a key perspective for understanding cultural development along the eastern Silk Road. Previous genetic and archaeological studies have revealed complex, multi-ethnic interactions in this region, shaped by migration and sociocultural exchange. However, the lack of structured linguistic data and computational tools for studying GQ language contacts has limited rigorous analysis of sociocultural evolution. Here, we presented a new hybrid dataset of phonological and morpho-syntactic features from languages sampled across the GQ region. We introduced a computational framework to assess language contact and admixture, allowing us to quantify interaction among GQ languages and trace their origins. Our results showed that GQ languages exhibit distinct contact patterns in their phonological and morpho-syntactic systems, with some languages displaying clear evidence of mixture. Using a new statistical method, Trait Sharing Among Languages (TSAL), based on tree topology, we identified significant influences from Sinitic, Tibetan, Mongolic, and Turkic languages in shaping the GQ linguistic diversity. These findings highlight the GQ region as a linguistic convergence zone on the eastern Silk Road, providing a foundation for quantitative research on language contact and admixture. Our work enhances the linguistic perspective on cultural evolution in the GQ region and supports future interdisciplinary studies that integrate languages, genes, and material cultures.