http://en.wikipedia.org/wiki/Help:IPA_for_Cantonese
http://en.wikipedia.org/wiki/Cantonese_phonology
I don't know any other way to explain this outside of what's on the 2nd link...
The position of the coronal affricates and sibilants /t͡s/, /t͡sʰ/, /s/ are usually alveolar ([t͡s], [t͡sʰ], and [ s ]), but can be postalveolar ([t͡ʃ], [t͡ʃʰ], and [ʃ]) or alveolo-palatal ([t͡ɕ], [t͡ɕʰ], and [ɕ]), especially before the front high vowels /iː/, /ɪ/, /yː/.
...there are more sounds than the jyutping romanizations z/c lead one to believe. You might be hearing/perceiving what you term the "hard" sounds in syllables like 字 and 癡, versus that of 渣 and 茶.
-Tony
http://en.wikipedia.org/wiki/Cantonese_phonology
I don't know any other way to explain this outside of what's on the 2nd link...
The position of the coronal affricates and sibilants /t͡s/, /t͡sʰ/, /s/ are usually alveolar ([t͡s], [t͡sʰ], and [ s ]), but can be postalveolar ([t͡ʃ], [t͡ʃʰ], and [ʃ]) or alveolo-palatal ([t͡ɕ], [t͡ɕʰ], and [ɕ]), especially before the front high vowels /iː/, /ɪ/, /yː/.
...there are more sounds than the jyutping romanizations z/c lead one to believe. You might be hearing/perceiving what you term the "hard" sounds in syllables like 字 and 癡, versus that of 渣 and 茶.
-Tony