No no no, those language pack for player is for change the player user interface language only.
those chinese song is mp3 rite?
as far as i know only mp3 have this kind of problem coz some stupid player still use the OLD id3v1 which doesnt support unicode,
well those chinese character will saved as ASCII instead and only works if user change the Windows locale to Chinese Taiwan(Traditional)/China(Simplified).
Make it short,
1. Use applocale, load the player with applocale and change the language to Chinese traditional/simplified.
2. Use itunes, if itunes is able to read those charater correctly, change the Tags to ID3v2.4
3. Try xmplay, it can displayer both ID3v1 and v2.
here is the prooooof:
» Click to show Spoiler - click again to hide... «
As you can see, Id3v1 simply failed at failing.