right click on the video window and a menu pops up.. select the one that says audio.. if the video file has dual audio options you can change it there..
you could try this not sure if it works though.. Close the VLC player.
Open file vlcrc in textedit located in folder ~/Library/Preferences/VLC/
search for audio-language=
by default there is nothing after equal sign, and there is nowhere in preferences to set the default language. Just type your preferred languages separated by comas, after equal sign. Make sure you do not leave any spaces after "=" and and comas. For English and Japanese languages it should Look like this: audio-language=English,Japanese. You must type in Japanese after English, because if you don't you wont hear a thing when a media file will have only Japanese audio track.
