Cantonese phonology

The standard pronunciation of Cantonese is that of Guangzhou, also known as Canton, the capital of Guangdong Province. Hong Kong Cantonese is related to the Guangzhou dialect, and the two diverge only slightly. Yue dialects in other parts of Guangdong and Guangxi provinces, such as Taishanese, may be considered divergent to a greater degree.

A syllable generally corresponds to a word or character. Most syllables are etymologically associated with either standard Chinese characters or colloquial Cantonese characters. Modern linguists have discovered there are about 1,760 syllables being used in the entire Cantonese vocabulary, which cover the pronunciations of more than 10,000 Chinese characters. Therefore, the average number of homophonous characters per syllable is six. Phonetically speaking, a Cantonese syllable has only two parts – the sound and the tone.

A Cantonese sound (or sound segment) usually consists of an initial (onset) and a final (rime). There are about 630 sounds in the Cantonese syllabary.

Some of these, such as /ɛː˨/ and /ei˨/ (欸), /poŋ˨/ (埲), /kʷeŋ˥/ (扃) are no longer common; some, such as /kʷek˥/ and /kʷʰek˥/ (隙), or /kʷaːŋ˧˥/ and /kɐŋ˧˥/ (梗), have traditionally had two equally correct pronunciations but are beginning to be pronounced with only one particular way by its speakers (and this usually happens because the unused pronunciation is almost unique to that word alone), thus making the unused sounds effectively disappear from the language; some, such as /kʷʰɔːk˧/ (擴), /pʰuːy˥/ (胚), /tsɵy˥/ (錐), /kaː˥/ (痂), have alternative nonstandard pronunciations which have become mainstream (as /kʷʰɔːŋ˧/, /puːy˥/, /jɵy˥/ and /kʰɛː˥/ respectively), again making some of the sounds disappear from the everyday use of the language; and yet others, such as /faːk˧/ (謋), /fɐŋ˩/ (揈), /tɐp˥/ (耷) have become popularly (but erroneously) believed to be made-up/borrowed words to represent sounds in modern vernacular Cantonese when they have in fact been retaining those sounds before these vernacular usages became popular.

...
Wikipedia