Sounds kind of like "ds" in "bids", but voiceless.

ㄗˋㄐㄧˇ

oneself

自己

ㄗㄞˋㄐㄧㄢˋ

goodbye

再见

IPA: [t͡s]

Sounds kind of like "ts" in "cats".

ㄘˊ

word

ㄘㄜˋㄙㄨㄛˇ

bathroom

厕所

IPA: [t͡sʰ]

Sounds like "s" in "sick".

ㄙˋ

four

ㄙㄢ

three

IPA: [s]



Single-syllable audio courtesy of the AllSet Learning Chinese Pronunciation Wiki, used with permission.

HSK word audio courtesy of Audio-cmn. (CC BY-SA 3.0)