"Clear" and "turbid" in Chinese phonology

A key concept in traditional Chinese phonology is the distinction between "clear" (qīng 清) and "muddy / turbid / murky" (zhuó 濁).  Although it is mainly applied to the sounds of language, the qīng 清-zhuó 濁 distinction also has applications / implications for music.

Roughly speaking, the linguistic and musical correlations are qīng 清 ("clear; high pitch") and zhuó 濁 ("muddy; low pitch").  Also applicable to music are the wǔshēng 五聲 ("five musical tones [of the pentatonic scale])": gōng 宮, shāng 商, jué 角, zhǐ 徵, and yǔ 羽 — equivalent to do, re, mi, sol, and la in western solfège. (source)

I've often wondered how and when these terms arose, how they function in historical phonology, and how they correlate with usages in modern linguistics.  I asked several specialists in Chinese historical linguistics their opinion on these matters.

David Prager Branner:

How the terms function in historical phonology. Qīng 清 "clear" and zhuó 濁 "murky" describe absence or presence of voicing in syllable initials. Qīng means the absence of voicing and zhuó means its presence. Most syllable-initials in the Yùnjìng 韻鏡 (1161; 1203) system are classified as either qīng or zhuó, although there are also some classified as "qīngzhuó," about whose intended meaning there is argument. Correlation in modern linguistics. We normally explain the analogy by way of "murmur" or "breathy voice," something still widely heard in, famously, many dialects of the Wú group. This kind of initial-voicing sometimes appears to be a phonetic feature distinct from the segments of the syllable. When and how they arose. The contrast and the two specific terms qīng and zhuó seem to have originated in the late Nánběi Cháo period (386-589) — they appear together in Yán Zhītuī's (531-591) Jiāxùn 家訓, for instance. Just how they arose in phonetics is uncertain, but they are also known in musical terminology, from a much earlier period — they occur together in the Lǐjì, for instance. I have heard it said that they refer to normal vs. flatted musical pitch, which would offer a situation parallel to the effect of voicing on tone contours — syllables with a murmured-voice initial tend to begin with lower pitch than syllables in the same tone category but with a voiceless initial. But I am not certain this explanation is agreed on universally.

Tsu-Lin Mei, quoting Jerry Norman, Chinese (1988). 

On p. 33, there is a photo reprint of a page of the Yunjing rhyme table (a Song work).  Reading from right to left, there are 4 categories of initials, qīng 清, cìqīng 次清, zhuó 浊, qīngzhuó 清浊。

[VHM:  respectively voiceless unaspirated, voiceless aspirated; voiced; nasal stops.  (source)]

On p. 30 there is this explanation:

     The primary division of the initials is into qīng 'clear' and zhuó muddy'. Qīng designates the voiceless initials; the qīng initials are further divided into quánqīng 'completely clear', the voiceless unaspirated initials, and ciqing 'secondarily clear', the voiceless aspirated initials.  Quanzhuo 'completely muddy' refers to the voiced obstruents (stops, affricates and fricatives); there is evidence that in the late Tang standard language the quanzhup initials were pronounced as voiced aspirates or murmured stops, much like their descendants in certain contemporary Wu dialects.  The cizhuo or 'secondarily muddy' initials are the voiced sonorants.

How it correlates with concepts in modern linguistics?

Qing 'clear' correlates with voiceless initials.  Zhuo "muddy' correlates with voiced (obstruent) initials.  Cizhuo 'secondarily muddy' is no longer used.  Instead there is biyin 鼻音 nasals, bianyin 边音 laterals, etc.

Since the "clear" (qīng 清)-"muddy / turbid / murky" (zhuó 濁) distinction in phonological analysis emerged around the 4th-5th century when so many other important phonological concepts arose in China under the impact of Indian language science (brought primarily with Buddhism), I suspect that the qīng 清–zhuó 濁 distinction also has an Indian basis, but I've never been able to determine exactly what it was.

I asked Indian language specialists, "Does this "clear"-"muddy / turbid" distinction ring a bell with you in Indian language science?"

Patrick Olivelle replied:

That seems like a reasonable supposition to me.  Now we need to undertake how, when, and in what form this distinction was transferred to China.  It would also be desirable if there was anything in the etymological basis of ghoṣavant, and aghoṣa that would have suggested "clear" and "turbid / muddy / murky" to those who wished to translate them into Sinitic.  Since the qīng 清-zhuó 濁 distinction already occurred in musical analysis in China during the classical period, it must have been taken over ready-made for phonological analysis.

This post has raised a lot of questions, answered some of them, and points to further questions and answers from interested readers.  Above all, its main purpose is to introduce a key concept in historical Sinitic linguistics to modern linguists who previously may have been completely unaware of it.  Hopefully this will lead to fruitful interaction between the two fields.