Unlocking taunts in Super Street Fighter 4 is a bit different than it was in the previous version. You don’t unlock taunts for all characters at once like in Street Fighter 4, you just unlock them for each character by playing with that specific character a certain number of times.
All you have to do to unlock all of the taunts for any character is to play 15 matches. You’ll unlock a taunt every other match you play. The nice thing though is that you don’t have to completely finish any of the matches, all you have to do is start one, then quit.
The easiest way to do this is to go into Versus mode and select Player vs. CPU. Pick the character you want to unlock taunts for, and once the match starts press start and select Character Change, and do this until you’ve unlocked all of the taunts you want.
Note that while you’re at it, you’ll also be unlocking the costume colors as well.