Xu Chan 徐蕆 was a 12th-century scholar, who wrote a preface to the 韻補 ''Yunbu'' of 吳域

Wu Yu Wu Yu 吳域 (c. 1100-1154) was an early and important Chinese philologist and phonologist Phonology is the branch of linguistics that studies how languages or dialects systematically organize their sounds or, for sign languages, their consti ...

(circa 1100–1154) in which he first proposed the xiesheng hypothesis.Behr, Wolfgang. 2005. "Language Change in premodern China: notes on its perception and impact on the idea of a 'constant way'." ''Historical truth Historical Criticism and Ideology: Chinese Historiography and Historical Culture from a New Comparative Perspective''. Helwig Schmidt-Glintzerr, Achim Mittag, and Jörn Rüsen, eds. pp. 13-51, esp. 34.

References

12th-century Chinese writers Chinese scholars {{China-academic-bio-stub