This article describes a morphosyntactic feature of the Xining dialect that is unique among all Chinese dialects: that is, the use of a postposition to express ablative nominal relationships. The postposition [t[curly-tail lowercase c]ia] is invariably pronounced in the neutral tone and has no cognates in either earlier varieties of Chinese or among present Chinese dialects. The morpheme's origin is shown to have come from a neighboring non-Sinitic language. Moreover, the variations within the syntactic expression of the ablative are correlated with various sociolinguistic groups. These correlations suggest an ongoing change in the dialect's morphosyntactic system of a kind rarely observed among Chinese dialects. Finally, the process of linguistic change is correlated with demographic changes within the Xining region that show Xining is a place where language contact and rapid linguistic change are likely to be found.