Phonology of Old Chinese

Scholars have attempted to reconstruct the phonology of Old Chinese from documentary evidence. Although the writing system does not describe sounds directly, shared phonetic components of the most ancient Chinese characters are believed to link words that were pronounced similarly at that time. The oldest surviving Chinese verse, in the Classic of Poetry (Shijing), shows which words rhymed in that period. Scholars have compared these bodies of contemporary evidence with the much later Middle Chinese pronunciations listed in the Qieyun rime dictionary published in 601 AD, though this falls short of a phonemic analysis. Supplementary evidence has been drawn from cognates in other Sino-Tibetan languages and in Min Chinese, which split off before the Middle Chinese period, Chinese transcriptions of foreign names, and early borrowings from and by neighbouring languages such as Hmong–Mien, Tai and .

Although many details are disputed, most recent reconstructions agree on the basic structure. It is generally agreed that Old Chinese differed from Middle Chinese in lacking retroflex and palatal obstruents but having initial consonant clusters of some sort, and in having voiceless sonorants. Most recent reconstructions also posit consonant clusters at the end of the syllable, developing into tone distinctions in Middle Chinese.

Although many details are still disputed, recent formulations are in substantial agreement on the core issues. For example, the Old Chinese initial consonants recognized by Li Fang-Kuei and William Baxter are given below, with Baxter's (mostly tentative) additions given in parentheses:

Most scholars reconstruct clusters of *s- with other consonants, and possibly other clusters as well, but this area remains unsettled.

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