[Kali]

is much strange that there is no option in xbmc to setting a default language for dvd playback, i have checked mplayer man and i have found "-alang <two letter country code>"
i have added it to mplayer.conf and it works

mplayer.conf
alang=<two letter country code>

example

alang=it

[Morien]

could this also work for ogm/mkv/dual audio avis?

[Gamester17]

could this also work for ogm/mkv/dual audio avis?

it doesn't work yet, but i've read in mplayer-dev-eng mailing-list that they are working on a common sub language selection for everything