Proto-Sino-Tibetan (PST) is thelinguistic reconstruction of theSino-Tibetanproto-language and the common ancestor of all languages in it, including theSinitic languages, theTibetic languages,Yi,Bai,Burmese,Karen,Tangut, andNaga.Paul K. Benedict (1972) placed a particular emphasis onOld Chinese,Classical Tibetan,Jingpho,Written Burmese,Garo, andMizo in his discussion of Proto-Sino-Tibetan.^[1]

While Proto-Sino-Tibetan is commonly considered to have two direct descendants,Proto-Sinitic andProto-Tibeto-Burman,^[2] in recent years several scholars have argued that this was not well-substantiated,^[3] and have taken to calling the group "Trans-Himalayan".^[4] In this case, Proto-Tibeto-Burman may be considered as equivalent to Proto-Sino-Tibetan ifSinitic is indeed not the first branch to split from Proto-Sino-Tibetan.^[5]

Reconstructed features include prefixes such as the causatives-, the intransitivem-, the miscellaneousb-,d-,g-, andr-, suffixes-s,-t, and-n, and a set of conditioning factors that resulted in the development oftone in most languages of the family.^[6] The existence of such elaborate system of inflectional changes in Proto-Sino-Tibetan makes the language distinctive from some of its modern descendants, such as theSinitic languages, which have mostly or completely becomeanalytic.

Proto-Sino-Tibetan, likeOld Chinese, also included numerous consonant clusters, and was not atonal language.

The table below shows consonant phonemes reconstructed by Benedict.^{[1][page needed]}

The reconstruction by Peiros & Starostin suggests a much more complex consonant inventory.^[7] The phonemes inbrackets are reconstructions that are considered dubious.

The following tables show the reconstruction of Proto-Sino-Tibetan phonemes by Nathan Hill (2019).^[8]

The consonants/ptkqʔmnŋlrj/ can take coda position, as well as the cluster/rl/. While Hill does not reconstruct/j/ as an initial consonant due to Baxter and Sagart's Old Chinese reconstruction lacking such a phoneme, he mentions that Jacques and Schuessler suggest a/j/ initial for some Old Chinese words due to potential Tibetan or Rgyalrongic cognates.^[10]

Hill also claims that his reconstruction is incomplete, as it does not account for Tibetic palatalization, proto-Burmish preglottalization, Sinitic aspirates, and the Sinitictype A and B distinction of syllables.

The sound correspondences cited by Hill (2019) are as follows. Hill bases his correspondences to Old Chinese off of the Baxter-Sagart reconstruction, and thus that reconstruction will be used in the following correspondence tables.

Note that many cognate sets with/ptkbdg/ initials between Old Chinese, Tibetan and Burmese agree in every phoneme in a given wordexcept for whether an initial consonant is voiced or not. Jacques explains these discrepancies as at least partially triggered by pre-syllables that were lost or decayed on the way to Chinese, Tibetan and Burmese.^[11]

In Gong Huangcheng's reconstruction of the Proto-Sino-Tibetan language, the finals *-p, *-t, *-k, *-m, *-n, and *-ŋ in Proto-Sino-Tibetan remained in Proto-Sinitic and Proto-Tibeto-Burman. However, in Old Chinese, the finals *-k and *-ŋ that came after the close vowel *-i- underwent an irregular change of *-k＞*-t and *-ŋ ＞*-n. In Proto-Tibeto-Burman, *-kw and *-ŋw underwent a sound change to become *-k and *-ŋ respectively, while in Old Chinese those finals remained until Middle Chinese, where the finals underwent the same sound change.^[12]

Furthermore, in Proto-Tibeto-Burman, the finals *-g, *-gw, and *-d underwent the following changes:

1. *-d＞*-y
2. *-gw＞*-w
3. *-g＞*-w when it follows the vowel *-u-
4. *-g＞*-∅ when it follows the vowel *a and *-a-.

Words which do not have reliable Sinitic parallels are accompanied by a (TB).

• Proto-Tibeto-Burman language

For a list of words relating to Proto-Sino-Tibetan language, see theProto-Sino-Tibetan language category of words inWiktionary, the free dictionary.

• Hill, Nathan W. (2012),"The six vowel hypothesis of Old Chinese in comparative context",Bulletin of Chinese Linguistics,6 (2):1–69,doi:10.1163/2405478x-90000100.
• Hill, Nathan W. (2019).The Historical Phonology of Tibetan, Burmese, and Chinese. Cambridge: Cambridge University Press.doi:10.1017/9781316550939.ISBN 978-1-316-55093-9.
• Matisoff, James A. (2003),Handbook of Proto-Tibeto-Burman: System and Philosophy of Sino-Tibetan Reconstruction, Berkeley:University of California Press,ISBN 978-0-520-09843-5.

• Sino-Tibetan languages
• Proto-languages

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