It's known that dogs learn new tricks and behaviors through vocal sounds. So how do you train a deaf dog without using sounds and words?
A good way would be by tapping on the ground because dogs have the ability to feel vibrations and can react to where they were coming from.
Verbal praise like "good boy" won't work for a hearing impaired dog. But you can always use treats, toys or physical affection to reward desired behavior. You can also use a hand signal for the good work he did.
Without being able to vocally communicate with your deaf dog, you will have to rely on the ability for him to understand sign language. Like you would choose a word for a dog with regular hearing ability, you now have to choose a gesture for each command.
Always be as clear as possible and don't overwhelm yourself or your dog. Take baby steps and don't expect your deaf dog to know everything from day one.