I agree that every child does this at some point or another, but I hate to use the word "phase", although I admit that I just used it for the first time on another post, talking about the "whiny phase". Anyway, you are the parent, and if you chalk everything up to phases, you are ignoring the fact that the current behavior needs to be dealt with. Instead of looking at things as a phase, look at them as "learning experiences". Because a child is constantly learning, not going through phases, if they're phases, than they're phases of learning. So, tell her WHY other people call you and their daddy by their first names, and tell her that since YOU are their mommy, they need to call you mommy. You are not other people's mommy, so they call you B.. That's what I did with my kids, they were just mimicking what other people were calling me, but it never became an issue, I just told them what they were supposed to call me, and they were fine with that, and if they called me "Julie" I would look at them and say "No, I'm your mommy. Say 'Mommy' "