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 reading pronunciations listed in the Qieyun rhyme 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, Kra-Dai and Vietic languages.

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.

Overview

Most scholars believe that Old Chinese morphemes were overwhelmingly monosyllabic, though some have recently suggested that a minority of them had minor presyllables (but were still written with a single character).

Although many details of the sound system are still disputed, recent formulations are in substantial agreement on the core issues. For example, a recent synthesis gives the following inventory of initial consonants: + Old Chinese initial consonants Labial Dental Velar Uvular plain sibilant plain labialized plain labialized Stop oraffricate voiceless aspirate voiced Nasal voiceless voiced Lateral voiceless voiced Fricative orapproximant voiceless voiced Uvular stops are a relatively recent proposal, replacing , , and their labialized counterparts, and are not accepted by all authors. Baxter and Sagart reconstruct uvular stops together with and .

Most scholars also reconstruct several initial consonant clusters. In most reconstructions since the 1990s, an Old Chinese syllable also has some representation of the distinction between Middle Chinese "type-A" and "type-B" syllables, for example type A having pharyngealized initial consonants or long vowels (see ), an optional medial (or sometimes ), one of six vowels:

an optional coda, which could be a glide or , a nasal , or , or a stop , , or (with some authors also including ), an optional post-coda or . In such systems, Old Chinese, unlike later forms of Chinese, has no tones. The rising and departing tones of Middle Chinese are treated as reflexes of the Old Chinese post-codas.

Sources

Phonological system of the Qieyun

The reconstruction of Old Chinese typically starts from "Early Middle Chinese", the phonological system of the Qieyun, a rhyme dictionary published in 601, with many revisions and expansions over the following centuries. According to its preface, the Qieyun did not record a single contemporary dialect, but set out to codify the pronunciations of characters to be used when reading the classics, incorporating distinctions made in different parts of China at the time (a diasystem).

The Qieyun and its successors grouped characters by tone class, rhyme group and homophone group. The pronunciation of each group of homophonous characters was indicated using the fanqie method, using a pair of other words with the same initial consonant and final (the rest of the syllable) respectively. Analysis of the fanqie spellings allows one to enumerate the initials and finals of the system, but not to determine their phonetic values.

The rhyme tables from the Song dynasty classify the syllables of the Qieyun using a sophisticated feature analysis of the initials and finals, though influenced by the different pronunciations of that later period. Scholars have attempted to determine the phonetic content of the initials and finals by comparing them with the rhyme tables and by examining pronunciations in modern varieties and loans in Japanese, Korean and Vietnamese (the Sinoxenic materials), but many details regarding the finals are still uncertain.

Phonetic elements of the script

Each character of the script represented a single Old Chinese morpheme, originally identical to a word. The system does not use symbols for individual sounds as is done in an alphabetic system. However, while a minority of words are represented pictorially, most are written by borrowing characters for similar-sounding words. Often a disambiguating semantic indicator element was added to the phonetic element, yielding a phono-semantic compound. Often words written with a shared phonetic element are still pronounced alike, as in the word ('middle', ), whose character was adapted to write the words ('pour', ) and ('loyal', ).GSR 1007a,p,k. In other cases words sharing a phonetic element have very different sounds in any known variety of Chinese, but are assumed to have been similar in sound at the time the characters were chosen.

The first systematic study of the structure of Chinese characters was the Shuowen Jiezi (100 AD) written by Xu Shen. The Shuowen was mostly based on the small seal script standardized in the Qin dynasty. Earlier characters from oracle bones and Zhou bronze inscriptions often reveal relationships that were obscured in later forms. However, these brief and formulaic texts used only a small part of the lexicon. Since the late 20th century, several caches of bamboo and wooden slips from the Warring States period have been recovered, especially from the states of Chu and Qin. These texts feature considerable variation in the characters used to represent a word. The study of these variants can clarify both the pronunciations of individual words and also which phonetic elements were considered interchangeable.

Poetic rhyming

The other large body of contemporaneous evidence is rhyme in ancient texts. Most work has focussed on the Shijing, a collection of songs and poetry from the 11th to 7th centuries BC. Again some of these songs still rhyme in modern varieties of Chinese, but many do not. For many centuries, this was attributed to lax rhyming practice or varied pronunciations. The puzzle was solved by the late-Ming dynasty scholar Chen Di, who demonstrated that rhyming practice was consistent within the Shijing. Observing that language varied between places, he postulated that sounds changed over time, explaining the discrepancy.

The systematic study of Old Chinese rhymes began in the 17th century, when Gu Yanwu divided the rhyming words of the Shijing into ten rhyme groups ( ). These groups were subsequently refined by other scholars, culminating in a standard set of 31 in the 1930s. One of these scholars, Duan Yucai, stated the important principle that characters in the same phonetic series would be in the same rhyme group, making it possible to assign almost all words to rhyme groups.

Modern Chinese varieties Modern Min dialects, particularly those of northwest Fujian, show reflexes of distinctions not reflected in Middle Chinese. For example, the following dental initials have been identified in reconstructed proto-Min: Voiceless stops Voiced stops Nasals Laterals Example word Proto-Min initial *t *-t *th *d *-d *dh *n *nh *l *lh Middle Chinese initial Other points of articulation show similar distinctions within stops and nasals. Proto-Min voicing is inferred from the development of Min tones, but the phonetic values of the initials are otherwise uncertain. The sounds indicated as *-t, *-d, etc. are known as "softened stops" due to their reflexes in Jianyang and nearby Min varieties in northwestern Fujian, where they appear as fricatives or approximants (e.g. < *-p *-t *-k in Jianyang) or are missing entirely, while the non-softened variants appear as stops. Evidence from early loans into Mienic languages suggests that the softened stops were prenasalized. The distinction among resonants is also reflected in some Hakka varieties.

The Waxiang dialects of western Hunan differ strongly from other Chinese varieties, preserving several distinctions and features not found in the Qieyun.

Other evidence

Several early texts contain transcriptions of foreign names and terms using Chinese characters for their phonetic values. Of particular importance are the many Buddhist transcriptions of the Eastern Han period, because the native pronunciation of the source languages, such as Sanskrit and Pali, is known in detail. Commentaries on the classics from the same period contain many remarks on the pronunciations of particular words, which has yielded a great deal of information on the pronunciations and even dialectal variation of Eastern Han Chinese.

Many students of Chinese have noted "word families", groups of words with related meanings and variant pronunciations, sometimes written using the same character. One common case is "derivation by tone change", in which words in the departing tone appear to be derived from words in other tones. Another alternation involves transitive verbs with an unvoiced initial and passive or stative verbs with a voiced initial, though scholars are divided on which form is basic.

Old Chinese interacted with neighbouring languages, some of whose relatives, particularly Austroasiatic, Kra–Dai and Miao–Yao languages, are still spoken today. The earliest borrowings in both directions provide further evidence of Old Chinese sounds, though complicated by uncertainty about the reconstruction of early forms of those languages.

Structure of the Qieyun system

In the rhyme table tradition, initials were classified by place and manner of articulation. The initials of the Qieyun are slightly different from the rhyme tables, but are generally agreed and each traditionally named with an exemplary word as follows:

+ Initials of Early Middle Chinese with traditional names and Baxter's notation Labial Dental Retroflexstop Dentalsibilant Retroflexsibilant Palatal Velar Laryngeal Stop oraffricate voiceless aspirate voiced Nasal Fricative voiceless voiced Approximant

As many potential combinations of initial and final did not occur, the designers of the rhyme tables saved space by separating finals with different patterns of co-occurrence, effectively identifying cases of complementary distribution. Thus finals are split between divisions ( ) named I, II, III and IV based on the rows of the rhyme tables in which they were placed. Most scholars believe that finals of divisions I and IV contained low back and mid front vowels respectively, while Division II has a front lax vowel. Division III is usually taken as indicating a palatal medial in Middle Chinese.

Division III finals occur in more than half of the syllables of the Qieyun. Some authors call them type B finals, with type A encompassing all the other divisions. Comparing placement in the rhyme tables with distribution in the Qieyun, Li Rong subdivided division III finals into four distributional classes, which others have called pure (or independent), mixed and two kinds called chongniu. Some of the distinctions between the resulting seven classes are found only in the rhyme tables. When considering the Qieyun only, they reduce to four distinct patterns of co-occurrence with initials at various places of articulation:

+ Co-occurrence of classes of Qieyun initials and finals, with example syllables corresponding to the Shijing rhyme class Qieyun final type Qieyun initial type Labial Dental Retroflexstop Dentalsibilant Retroflexsibilant Palatal Velar Laryngeal Type A Divisions I and IV Division II Type B(div. III) Pure and chongniu-4 Mixed and chongniu-3