Mine did not bark till 12-13 weeks and when she did pretty sure it scared her more than me. She is 18 weeks now and to this day very very rarely ever barks. She barked last night when hubby came home from work really really later than normal (1am) and her and I were in bed. She heard his truck pull up and went crazy untill he came in the bedroom to show her it was him. Then she layed down and went back to sleep. I dont know if it scared her or if she was barking to protect or if she was just happy he was home. She knows the sound of his truck but not used to hearing it at 1am. (Gotta love the life of a farmers wife)
Other than that I bet since the first bark I have only ever heard her bark 2 maybe 3 other times.