Our Toto doesn't bark except when we allow her to ... playing, etc. She decided to bark the second day we had her ... we put her in her crate for a nap and she started barking. We read that when they do something you don't like, you should do something they don't like. So, a few little taps on the metal part of her crate and she hasn't done it since!
She's very good about it and quickly learned the word "no" ... so we just tell her "no bark" and she stops. They are so smart!