Baby talk and comforting is not something I would suggest either - "happy talk" and maintaining an upbeat attitude (without consoling) is what the behaviorist I know suggested.
Laughing works very well too, if you can manage it. I have started laughing when a strange dog approached, and it did wonders.
Some people sing "Happy Birthday" or some other silly song.
This isn't directly praising them for the behavior - it's leadership by example, I think. If Mom is nonchalant, then everything must be OK.