This book studies the Tangwang language, providing the first comprehensive grammar in English of this Chinese variety, with detailed analysis of its phonology, morphology, and syntax. This fills a gap in the literature, as previously only a few articles on this language were available. The book takes an interdisciplinary approach, examining genetic data to determine historical patterns of population migration, as well as linguistic data that focus on the influence of the Dongxiang (Santa) language as a consequence of language contact on the Silk Road. The concluding chapter argues that Tangwang has not yet become a mixed language, and that syntactic borrowing has a stronger impact than lexical borrowing on languages.