I'm really at a loss here, since I'm not an expert in character sets at all. So any expertise on this is welcome ...
AFAICT, everything works fine when the page is using the proper character set for the language and characters you want to enter, i.e. when you want to use chinese characters, you would have to serve the page in Big5 or GB2312 encoding.
When you switch to the english language file, the character set also switches to iso-8859-1 and that causes the problems we see.
In other words - I don't think there's anything that Geeklog could do here. If you want to use chinese characters, you will have to use the chinese character set (and not iso-8859-1).
As I said, I could be wrong. So anyone with more experience in foreign (especially Asian) languages, please feel free to correct me ...
bye, Dirk