My parents dog, Noah, my beloved friend growing up has grown deaf in his old age. He is a 14 year old Labrador dalmatian mutt (we know his exact parentage because he was an adoption from another military family when he was two). We know he has always been hard of hearing, but not completely deaf. Now age took its toll. We are sure to stomp on the ground a few times if we need to wake him for potty calls or other things. He would never bite us, but he can be startled if we touch him and he was sleeping. He is mostly the same, it can just be difficult finding him sometimes when he is sleeping somewhere in the house, since he can't hear us calling him!
My neighbors dog who I petsat a lot growing up became blind and deaf in her old age too. I was also the go-to gal for weekend petsitting, letting her out in the afternoon after school, etc. because she adored me. She was kind of a one family dog and wary of nearly all strangers, but somehow accepted me into her pack. When she was going deaf she was very hard to find in the house, just like Noah! I hated having to look in bedrooms for her (I consider that off limits since that is personal space) but I had to to find her sometimes, lol. I did some foot stompies, she would wake up and then be all excited because even though she was blind, she knew my scent. Her blindness wasn't a huge issue, since they made sure not to rearrange any furniture, so she knew where to go. I sometimes had to lead her back to the house from in the yard time, though, I just put my hand on her shoulder and walked, and she followed my lead. Gosh, she was such a sweetheart, I miss her dearly (she passed away at the ripe old age of 16 last year).
In both cases, since the dogs were elderly, no additional training was or has been done. However, my aunt's adopted German shepherd, who was only two years old and as deaf as a post from many untreated ear infections, learned sign language very quickly. He was the typical GS, smart as a whip and eager to please.