@dalehileman,
I remember reading that this can be related to one having a hearing problem. I don't know how true that is, much less if you have a hearing problem yourself.
Since I do, and don't have hearing aids, I sometimes ask people if I talk too loud, and they tell me no, I don't, but I bet that I do talk too loud on the phone sometimes.
Anyway, you might check with an audiologist, if you haven't already.