if that were my dog barking all day I would hope it would lose its voice! but I don't think so. I have neighbors whose dogs haven't stopped barking since the day they were born and they never lost its voice. but, just like humans, overuse of vocal cords may come back to bite him( no pun intended :-) later if he/she does not stop. I would try to calm your dog down though and figure out what's making it bark so much.