How silly is silly

We have two of Gwenchik's uncles visiting us from Indiana. She is thrilled that they came to visit and overwhelmed with all the attention. They go for all day sessions at MIT and every morning Gwenchik's wants to know when they will have the reserved time
to play just with her.

This morning, we were going as usual to her MindLab class, and all of a sudden she wanted the uncles to leave earlier for MIT. So while driving to class, I asked why?

Gwen: Mom, they are really, really silly most of the time. They speak really fast and say only nonsense. Probably grown up nonsense, but I do not understand what is so funny most of the time.
Me: So do you what them to stay at MIT longer, because it seems like they are too grown up for you?
Gwen: Oh, no. They have to come and read me a story tonight and play with me. I just have to rest, get enough sleep and maybe you can read me a book in a way that actually make sense. Then I can just watch them being silly. It is really funny and I do not think they understand that they are silly, do you?
......
Later, on the way back continuing conversation.
Me: You know, you can probably tell them when they are being too silly and you do not understand them.
Gwen: I tried several times, but they keep talking about strange things and continue to be silly. Of course, I can tell them that I will not kiss them good night if they won't read they book like everyone else---but that is really not nice. So I just wait...