first you do some fights if you won some you get dev. points if you got 2500 you can
unlock a new style

if u play def jam for fight psp vision
type in square,up,down,cirle,left,right
that the cheat code for def jam
Happy playing.

you need 2500 points per additional fighting style you want to learn. I also know a few
styles:
Muaythai (UFC KICKBOXING) = KICKBOXING + 2SUBMISSIONS
JEET KUNE DO = MARTIAL ARTS +2SUBMISSIONS
As you can see I like mixing submissions into my fighting styles. Hope this helps