stylistic:tone, linguistic:voice_change
Phonology

Syllables in the Chinese languages have some unique characteristics. They are tightly related to the morphology and also to the characters of the writing system, and phonologically they are structured according to fixed rules.

The structure of each syllable consists of a nucleus that has a vowel (which can be a monophthong, diphthong, or even a triphthong in certain varieties), preceded by an onset (a single consonant, or consonant + glide; a zero onset is also possible), and followed (optionally) by a coda consonant; a syllable also carries a tone. There are some instances where a vowel is not used as a nucleus. An example of this is in Cantonese, where the nasal sonorant consonants /m/ and /ŋ/ can stand alone as their own syllable.

In Mandarin much more than in other spoken varieties, most syllables tend to be open syllables, meaning they have no coda (assuming that a final glide is not analyzed as a coda), but syllables that do have codas are restricted to nasals /m/, /n/, /ŋ/, the retroflex approximant /ɻ/, and voiceless stops /p/, /t/, /k/, or /ʔ/. Some varieties allow most of these codas, whereas others, such as Standard Chinese, are limited to only /n/, /ŋ/, and /ɻ/.

The number of sounds in the different spoken dialects varies, but in general, there has been a tendency to a reduction in sounds from Middle Chinese. The Mandarin dialects in particular have experienced a dramatic decrease in sounds and so have far more polysyllabic words than most other spoken varieties. The total number of syllables in some varieties is therefore only about a thousand, including tonal variation, which is only about an eighth as many as English.