Tools->
Preferences (if you're in "view all" mode, change to simple mode)->
Audio
The last option under General Audio is
Preferred audio language and a text box; here, you can specify a list of
two- or three-letter ISO-639 language codes separated by commas but no spaces. List the codes in order of priority, and the player will look for the first language in the list as default, before moving on to the second. For example this entry from my settings:
jpn,swe,eng
will always play the Japanese audio track by default. If the file has no Japanese audio, the Swedish track will be played instead. Only if neither Japanese nor Swedish are present will VLC look for and play any English tracks.
You can do the same thing for choosing subtitle languages in
Tools->
Preferences ->
Subtitles & OSD->
Subtitles Language->
Preferred Subtitles Language
Hope this helps
M. Northstar