Hi egalitarian,
it would be fine, if you'll translate the interface of Mp3tag 
Simply pick up the file mp3tag.lng from Mp3tag's program-directory. There are many ordered strings per line with some placeholders (for filenames, folderpaths, etc.) like %s and %d. Please keep these placeholders. A & character signals the shortcut character via ALT+x.
Happy translating!
~ Florian