A few people, myself included, had made threads complaining that their audible touch tones did not sound when manually dialing a phone number. Instead it'd vibrate and do nothing else.
My phone has had this problem since I got it. Somedays the touch tone was there, other days it was not. Then I realized the problem. The audible touch tone is configured based off the media volume, not the phone volume. DUH ><
Crank up your media volume and try manually dialing a number (if you have this problem) and it should work.