Distance-dependent linguistic diffusion from sociocultural centers in China

This study employs dialectometric methods to test wave theory’s predictions of linguistic diffusion, examining how geographical distance from major sociocultural centers shapes linguistic similarity in China. Analyzing 32 phonological, lexical, and morphosyntactic features across 243 locations, we calculate Jaccard similarity coefficients relative to the national center (Beijing), a major regional center (Guangzhou), and a non-center control (Baoxing). Results confirm a strong negative correlation between distance and similarity for both Beijing (r ≈ −0.72) and Guangzhou (r ≈ −0.78), but not Baoxing (r ≈ −0.25), validating distance-decay as a key mechanism. However, significant differences in the pattern and extent of influence emerge. Beijing exhibits a wider influence radius (~1195–1491 km) but with a shallower, noisier decay slope and strong directional anisotropy, reflecting its role as a sociocultural core whose reach is mediated by historical migration corridors. Guangzhou demonstrates a steeper, more geographically confined decay profile (~672–877 km radius), functioning as a regional center. However, as a national center, Beijing’s linguistic influence is not nationwide. We argue that the contemporary linguistic state results from the historically recent ascendancy of Beijing Mandarin superimposed upon older substrates, mainly the Nanjing Mandarin. The findings highlight the interplay of genealogical, contact-based, and spatially explicit models of the evolution and distribution of Sinitic languages.