This only worked for me during an online head to head game. I shouted at my kinect many times to no avail. When you play online head to head there is an obvious microphone in the bottom middle of the screen. I got the achievement by calling the audible. I didn't even snap the football before I popped the achievement.
I hope it is available for other game modes, but if you do not see the microphone icon on the bottom of the screen don't bother shouting at your kinect like I did.