IAMCELEB™ - Banu
Banu is a very quiet and well-behaved dog.
He will rarely bark, whether he is happy or not. I even thought he was congenitally incapable of barking for the first two months.
One day I accidentally fell asleep in the bath and forgot I was boiling water until I was awakened by Banu's barking and scratching at the door. Thanks to Banu I found out just in time, when the kettle was dry and already starting to smoke.
I still don't know what BB's reason for not barking is, but I think it's enough that he would bark loudly for me in a critical situation.