I can confirm that LimeWire already includes in its beta version a menu option to change the language to one that is supported (it requires restarting LimeWire).
Not all translations are complete, but if you want to participate, look into
http://www.limewire.org/translate.html for how you can help providing more translations or completing the existing ones.
Also note that some languages won't display correctly with all themes. For now, the only themes which can display (at least on Windows) all languages are "Amber", "Classic", and "Halloween".
With some languages, it is necessary to revert the custom font names set in the "theme.txt" file from "Vardana" back to its default "dialog" font name (needed for Arabic, Chinese and Japanese, and further for all other non Latin-based languages that can't be displayed with the "Verdana" font).
May be we will try investigating on how to set a font family instead of just a single font in themes. Or we could just add the default "dialog" logical font name can display all languages supported by Java.
The "default"/"LimeWire" (or "LimeWirePro") themes works but only for one script (you can't display simultaneously Cyrillic, Arabic, Simplified Chinese, Traditional Chinese, Japanese Hirgana/Katakana). I think this will be fixed (this comes from the font selection which do not support all scripts simultaneously).
So to change to a supported script, you must first make sure to use a theme that displays the native language name correctly in the Language selection menu.
To display Arabic, Chinese or Japanese make sure you select an appropriate theme and that your Java installation is "international" and your native system is installed with the corresponding fonts needed for this language, before applying a new language, or you'll get many labels and items displayed as unreadable white boxes...