I am a new owner, so I probably don't know much, but I can tell you that Mocha is very quiet. I think she was naturally a quiet one, I noticed that when I saw her at the breeder's. So far in 2 months I have heard her bark maybe 10 times. A few times when I left her upstairs alone to get something downstairs, other times to tell my shihtzu to shut it basically
I have left her alone many times, although there is a shihtzu at home. But I left her alone in my room (her room, really) many times, just closed the door and do my stuff around the house, so far not a peep
She just sleeps and plays in her pen on her own.