Mandarin phonology

The initials of Sin Sukchu's standard readings (mid-15th century) differed from those of Late Middle Chinese only in the merger of two series of retroflexes: Sin's system had fewer finals than Late Middle Chinese. In particular, final stops -p, -t and -k had all merged as a final glottal stop, as found in modern Jiang-Huai Mandarin: This system had mid vowels [e] and [ɔ], which have merged with the open vowel [a] in the modern standard language. For example, and  are both guān in the modern language, but were distinguished as [kwɔn] and [kwan] in Sin's system. The Middle Chinese level tone had split into two registers conditioned by voicing of the initial, as in modern Mandarin dialects.

In comparison with Sin's standard readings, the major changes in the late Ming language described by European missionaries were the loss of the voiced initials and the merger of -m finals with -n. The initials ʋ- and r- had become voiced fricatives v- and ʐ- respectively. The glottal stop initial had merged into ŋ- before mid and low vowels, and both initials had disappeared before high vowels. By the early 18th century, the mid vowel [e]/[ɔ] had merged with [a]. However unlike the contemporary Beijing pronunciation, early 19th century Mandarin still distinguished between palatalized velars and dental affricates, the source of the spellings "Peking" and "Tientsin" for modern "Beijing" and "Tianjin".