Middle Chinese

Middle Chinese (simplified Chinese: 中古汉语; traditional Chinese: 中古漢語; pinyin: zhōnggǔ Hànyǔ), formerly known as Ancient Chinese is the system of Chinese pronunciation contained in the Qieyun, a rime dictionary first published in 601 and followed by several revised and expanded editions. The fanqie method used to indicate pronunciation in these dictionaries, though an improvement on earlier methods, proved awkward in practice. The 12th-century Yunjing and other rime tables incorporate a more sophisticated and convenient analysis of the Qieyun phonology. The rime tables attest to a number of sound changes that had occurred over the centuries following the publication of the Qieyun. Linguists sometimes refer to the system of the Qieyun as Early Middle Chinese and the variant revealed by the rime tables as Late Middle Chinese.

The dictionaries and tables describe pronunciations in relative terms, but do not give their actual sounds. The Swedish linguist Bernard Karlgren believed that the dictionaries recorded a speech standard of the capital Chang'an of the Sui and Tang dynasties, and produced a reconstruction of its sounds. However, based on the more recently recovered preface of the Qieyun, most scholars now believe that it records a compromise between northern and southern reading and poetic traditions from the late Southern and Northern Dynasties period. This composite system contains important information for the reconstruction of the preceding system of Old Chinese phonology (1st millennium BC).

The Middle Chinese system is often used as a framework for the study and description of various modern varieties of Chinese. Branches of the Chinese family such as Mandarin Chinese (including Standard Chinese, based on the speech of Beijing), Yue Chinese and Wu Chinese can be largely treated as divergent developments from the Qieyun system. The study of Middle Chinese also provides for a better understanding and analysis of Classical Chinese poetry, such as the study of Tang poetry.