
There is an elastic muzzle like contra\ption called a husher. It is made of four elastic panels, and means that the dog finds it very tiring to open it's mouth against the resistance.
My own breed can be vocal in a similar way, as they find the barking rewarding not only in itself but because it gets your attention, even if the atention is negative.
The only real solution is shock/surprise and then distraction to an alternative behaviour. I use water to spray right in the face/eyes in a jet, which stops them momentarily. I then praise for the desired, or alternative behaviour, use food also if that helps. Your timing has to be spot on, and you must never show ammusement or make the water sporaying a game.
Works for my suburban living pack of Four.