Jake was 10 weeks when I brought him home, and his first really loud bark was when I came out of the bathroom with hair color on my hair. I think he was about 14 weeks. He barked at me, but then when I talked to him, he recognized my voice and realized that I was still mommy.
Jackson was 10 weeks, and he barked the day we brought him home. We had been home several hours, and he and Jake were checking each other out and getting used to each other. They were kinda starting to play, and they got into a barking match. It was so funny, it was like they were getting the rules straight from the beginning. After they were done barking, they started playing and having a good time!