A friend of mine's dalmation, Ax (yes, daddy was a fireman, their other dal was named Smokey) was deaf. They agreed to have him neutered so the breeder gave him to them free.
His owners had to teach him sign language for obedience commands. Instead of calling him they stamp their feet on the floor to get his attention. One of the first things he was taught was to always keep an eye on master and mistress.
The fewer the spots the higher the incidence of deafness. This is a common problem in dals, apparently 1 in 12 is born deaf. That is not, however, why they are firedogs.
Debunking from the Toledo Fire Museum.