Jack is right. But I think you probably want to know the difference between 知 and 識 instead. (識 also shares the same pronunciation with 悉) 知 is mainly used when asking about if others know about a fact. e.g. 你知唔知德國喺係歐洲? Do you know Germany is in Europe? 識 is mainly used when asking about if others know about other people or can perform a skill. e.g. 你識唔識Peter嘅細佬? Do you know Peter's younger brother? 你識唔識游水? Can you swim?

Sik kann man auch wie "kennen" nutzen. Z.b. Kennst du ihm? du kannst "Sik" antworten.

ok, thanks a lot Jack, Rocky and Amy_Lin, that makes it clear. So, both words mean "to know" but are used in a different context. I try to sum up the equivalents in english and german: Zi - means... English: "to know (about a fact) - did you know that Germany is in Europe?" (know from "Knowledge") German: "wissen (about a fact) - weisst Du, dass Deutschland in Europa liegt?" (wissen = Verb of "Wissen") Sik - means... English: "to know (how to) - Do you know how to swim?..or..Can you swim? German: "Weisst Du wie man schwimmt?...or..."Kannst Du schwimmen?" (kannst Du = can you) Thx a lot again!

If we ask someone:"Do you know what I say?" we say in Cantonese like "你知唔知我讲咩?" If we ask someone know somebady, we say:"你悉唔悉距？" Sometime they are the same meaning. For example: --"Do you know how to fix the computer?" --"I dont know." you can use zi" (知) or "sik" (悉) like"我唔知/悉". But I think "知" is more formal than "悉". Hope it can help you:)

In oral Cantonese, we use"知". 悉 is a formal way to express "know"