No, Chinese Practice is a program written for Windows XP

Windows 2000 are "officialy" unsupported but as far as I know, it's possible to run Chinese Practice under it; you should have Eastern Asian Languages Support installed. If you see error message "Class not registered" try installing Chinese TTS (from your Windows or Office install disk, or you can download it here) Still some functions might be limited.

Yes, actually any language as long as you have the required font installed. In case of Arabic and other languages written from right to left you'll need to change text direction in Options | Fonts dialog. Of course all the advanced features like the dictionary or the text reader are Chinese specific.

If you install new version over an old one (or reinstall), pin yin characters may not show properly - in this case restart your computer. It seems that registering already registered font causes problem.

Click Options | Fonts, check Force Hanzi Font, select Simplified Chinese or Traditional Chinese and in the above droplist you'll see only chinese fonts. In the sample window you'll see how the selected font looks like and when you position mouse cursor over the sample window, you'll see the name and location of the font file.