I had a deaf Boxer. Adopted two Labs, one of whom was deaf. Loved her. Sweet mellow dog. Only barked when she was happy, not at random noises.

I have used hand signals with all of my dogs and find they are more accurately received than voice.

The preference of dogs is nose - eyes - ears.
Humans are ears - eyes - nose.
So we meet in the middle with visual communication, especially informal body language.

Deafness is very common in dogs, especially in floppy eared breeds. Odd that the rescue org did not notice it but glad the dog connected with someone well experienced!