The same way you would any other language. 

http://www.romhacking.net/start/ is where you need to look first.

Then, you need to find a translator(Or translate the text yourself.), then you put the text back into the game. This is very over simplified, but it's basically what you need to do.

Let's keep the somewhat aggressive, elite comments out of it boys.

Read and go through the getting started section and then come back and ask a more specific question, and you're likely to get better help. As has been stated, the process is the same. The only thing that differs is you table having characters from other languages. Yes, you're going to need a table with HUNDREDS of characters to do a Chinese games. Hex editing a game is highly inefficient, especially if you're not very familiar with the language in question and have a hex editor capable of it. Personally, I don't know of any that do Chinese.

If you can't understand what the difference is between making an English and chinese table, replace the tiles with English letters and make it that way if it makes it easier. You'll soon see there really is no difference. It doesn't matter if there's 5 characters or 500. It's the same, only longer.