Deaf kittens are like all other kittens. They can learn just as quick through your body language. Of course he won't come when called, but perhaps you can teach him that when you stomp on the floor, that it's dinner time. He can feel the vibrations. All you have to do for litter box training is show him where it's at! Kittens usually learn quick that it's where they're supposed to go. You have to remember that cats don't really know what we're saying when we talk to them. They notice different pitches in our tone that tell them what we mean. Your deaf kitten can learn from your expressions and body language that when you're mad, you put your hands on your hips. Or when it's time to eat, you put your hand to your mouth. So on and so forth.