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I asume you have both the language files available for the core and the various modules (in your case chinese and english)?
I also asume you followed the instructions that came with the xlanguage module (readme.txt)?
Then it should work...
If both language directorys are available in the core language directory, you should be able to set both chinese and english as base language through the admin menu.
Check in your cache directory if the config file is created.