Are dogs more human than we think?

The other day my dog, Abby, was "talking" in her sleep. It all started with her oh so very busy morning. She got up, went outside, came back in, and went back to sleep. She wakes up a couple times during the day to go outside, then of course, always coming back in, eventually falling asleep. It was late afternoon when she was "talking" in her sleep. She started off with a few woofs and whines, but then she started mouthing human words. It literally looked like she was talking. It was like she was saying "what" and "no". I mean how do we really know if they can't really talk?