She has no problem understanding us. But we have one problem which is she does not know how to tell us that she needs to go to the bathroom. We have been basically timing it. We prefer to have her tell us when she needs to go rather than her depending on us. A deaf dog in this situation is no different than a normal dog - because she needs to give the signal to you, not you to her.
Some people use bells attached near the door that they can ring.
It's pretty easy to train them to do it. Just get them to paw at the door or bell with the use of a treat. When they get close enough to doing it, open the door and let them out. Continue over many repetitions. My personal opinion however is not to train them to do this.