Editing Consonant harmony (section)

===In Old Chinese===
[[Old Chinese]] probably had some constraint governing the shape of disyllables. According to modern reconstructions of [[Old Chinese phonology]], type A and B syllables almost never co-occur in a disyllabic word. In the latest reconstruction of Old Chinese phonology proposed by [[William H. Baxter|Baxter]] and [[Laurent Sagart|Sagart]] (2014), this type A vs. type B distinction can be traced back to the presence or the absence of [[pharyngealization]] respectively, cf. {{wikt-lang|zh|納}} {{transliteration|zh|ISO|nà}} < OC {{IPA|*nˤup}} "to bring into" (type A) and {{wikt-lang|zh|入}} {{transliteration|zh|ISO|rù}} < OC {{IPA|*nup}} "to enter" (type B) only differing by the [±pharyngeal] trait of the initial consonant. Onsets of type B syllables, lacking of pharyngealization, are subject to [[Palatalization (phonetics)|palatalization]] in [[Middle Chinese]] (indicated by a palatal medial ''-j-'' in Baxter's notation), while type A pharyngealized onsets failed to palatalize. In many ancient disyllabic words type A and type B characters do not mix, there are almost solely bisyllabic morphemes either with type A syllables, such as:

* {{wikt-lang|zh|蝴蝶}} {{transliteration|zh|ISO|húdié}} < MC {{transliteration|ltc|hu dep}} < OC {{IPA|*gˤa lˤep}} "butterfly"
* {{wikt-lang|zh|邂逅}} {{transliteration|zh|ISO|xièhòu}} < MC {{transliteration|ltc|hɛH huwH}} < OC {{IPA|*gˤre-s gˤro-s}} "carefree"
* {{wikt-lang|zh|窈窕}} {{transliteration|zh|ISO|yǎotiǎo}} < MC {{transliteration|ltc|ʔewX dewX}} < OC {{IPA|*ʔˤewʔ lˤewʔ}} "beautiful and gentle (said of a woman)"
or with type B syllables, including:
* {{wikt-lang|zh|麒麟}} {{transliteration|zh|ISO|qílín}} < MC {{transliteration|ltc|gi lin}} < OC {{IPA|*gə rən}} "[[Qilin]]" (a mythical beast)
* {{wikt-lang|zh|蟋蟀}} {{transliteration|zh|ISO|xīshuài}} < MC {{transliteration|ltc|srit srwit}} < OC {{IPA|*srit srut}} "cricket"
* {{wikt-lang|zh|參差}} {{transliteration|zh|ISO|cēncī}} < MC {{transliteration|ltc|tsrhim tsrhje}} < OC {{IPA|*tsʰrum tsʰraj}} "uneven, irregular"

Such pattern seems to suggest the existence of some sort of '''pharyngeal harmony''' in [[Old Chinese]].<ref>{{harvp|Miyake|2015}}.</ref> However, there are notable, though infrequent, exceptions to this tendency, manifesting in ancient compounds that are generally hard to analyze. From this list the following word is often mentioned:
* {{wikt-lang|zh|鳳凰}} {{transliteration|zh|ISO|fènghuáng}} < MC ''bjuwngH hwang'' < OC {{IPA|*N-prəm-s ɢʷˤaŋ}} "[[Fenghuang|Chinese phoenix]], fabulous bird"<ref>Possibly an old and opaque compound from {{lang|zh|風皇}} {{transliteration|zh|ISO|fēng huáng}} < MC ''pjuwng hwang'' < OC {{IPA|*prəm ɢʷˤaŋ}} "sovereign of the winds" with affixes ({{harvnb|Miyake|2015}}).</ref>