It is how we process daytime experiences, feelings in our dreams. My take would be that she's talking as her dream is progressing. The dream may be triggered by something she's experienced or thought about or not. The dream could or could not have the same characters or even seem closely related to experiences.
I often dream about houses in which I'm the mother or child. I think I'm dealing with a couple of issues. In one dream my mom is taking care of me. She's watching as I organize the house. I'm feeling happy. In another dream my mother isn't there. I'm on my own and am looking for her. I do have issues related to my mother. One is that I miss her. The first dream tells me she's still "here"and I'm able to do things required of living. In the second dream, I'm anxious, and perhaps wanting my mother's help. These interpretations fit with my life. Of course the dreams are much more complicated.
I suggest your daughter is working out an event or feeling in which she was bothered but didn't talk about. Or perhaps.about something intangible in the daylight. Not knowing what she said. I can't even guess.what the dream is about. We often have fears that aren't known to us and we are only aware of the situation when we're dreaming. I sometimes have dreams that are so scary I wake up. Infrequently, I can figure out why I was scared. Most of the time I can't.
If she seems curious about the dream and can remember parts of it, have her describe it and ask her what she thinks the dream was about. Tell her she sounded (frightened?) and give her an opportunity to decide if the dream.tells about something.
If she doesn't remember the dream, and you're concerned, you can tell her how you felt. Perhaps she will talk about the dream. Perhaps not. My mother did this with me. When I had bad dreams, I would crawl into her bed. She would talk about the dream until I relaxed and fell back to sleep. She would always talk about my feeling scared and how it was only a dream.
My daughter rarely remembered her dreams. There was one time that has become a family story. I wrote it down. Whew! I no longer remember what she said. She stood up in bed, said something, then plopped down on my head. She didn't wake up and didn't remember any of it. At the time this incident felt related to situation at the time. My sense, from her tone of voice and action, was "there that's done."
A dream could mean we're processing something. We talk out loud as a part of the dream. It's also like watching a movie sometimes. We're not involved.
I would not be concerned about how she expressed being bothered. If she is not asking about her dream, I'd consider it just a dream and not worry about it.