The language of your system and the language set for VLC do not match (IE the font is not installed) or there is a broken font on your system.
Open a DOS box and type: CD "C:\Program Files\VideoLAN\VLC" then type: vlc --language <data>
--language <data>
data=auto,en,en_GB,ca,da,de,es,fr,it,ja,ka,ko,nl,oc,pt_BR,ro,ru,tr,
zh_CN,zh_TW
Language
This option allows you to set the language of
the interface. The system language is
auto-detected if "auto" is specified here.
After selecting the two (or so
) letter code for your countries language press enter and when VLC opens check the menus. Assuming you can see everything go to preferences and press Save and close the player. The next time you ope the player normally you should see your language.
If this did not work, you have a broken font and this must be resolved at the system level by using your control panel to reinstall your primary language.