ProtoSinoTibetan

Proto-Sino-Tibetan is a hypothetical reconstructed language posited as the common ancestor of the Sino-Tibetan language family, which includes Sinitic languages (such as Mandarin and Cantonese) and Tibeto-Burman languages (including Tibetan, Burmese, and many other languages of the Himalayas and surrounding regions). The concept is used by historical linguists to explain systematic correspondences in sound, basic vocabulary, and morphology across these languages. Because it is not attested in writing, Proto-Sino-Tibetan is reconstructed through the comparative method, proposing a set of phonological, lexical, and grammatical features that might have existed before the split into daughter languages.

Reconstructing Proto-Sino-Tibetan involves analyzing regular correspondences among diverse languages and proposing probable proto-forms for core vocabulary and grammar. Scholars differ on specifics, and reconstructions of phonology, tone (whether tone existed in the proto-language or emerged later), and morphological patterns vary by researcher. The basic lexicon and function words are often used as the primary evidence, with the goal of producing a coherent, testable picture of the ancestor language. The degree of certainty diminishes as one moves beyond well-established correspondences.

Dating and homeland hypotheses place Proto-Sino-Tibetan several thousand years in the past, in East Asia, with proposed homeland areas ranging from northern China to the Tibetan Plateau and adjacent zones. However, precise timing and geography remain debated, and such estimates depend on methodological assumptions.

Scholarly implications include supporting a genetic link between Sinitic and Tibeto-Burman languages, while ongoing debates address internal subgroupings, contact phenomena, and the overall unity of the Sino-Tibetan family.