Reconstructing phylogeny from linkage diffusion: Evidence for cladistic hinge variation

Linkage models of language diversification (Ross 1988, François 2014) represent the slow differentiation of closely related sister languages via dialect continua. Such historical relationships are said to prevent the reconstruction of branchinternal phylogeny. A newly defined mode of linkage variation challenges this restriction. In cladistic hinge diversification, speakers of a geographically central variety mediate innovations between isolated extremes of a sub-branch, while all three daughter branches maintain evidence of their own exclusive innovations. The resulting pattern blends linkage relations with family relations. Following a contextual review, the paper presents supporting evidence for the distinction from the Phowa languages of southwest China (Ngwi < Burmic < Tibeto-Burman). Data analysis includes sociohistory, dialectometry and genetic linguistic components. The argument affirms both wave and tree models of language change, enabling an enriched understanding of focal, relic and transition areas and their influence on the leveling, development and diffusion of linguistic innovations.