Sometimes it's very appropriate or she echos the current prayer. Most of the time, it's entertaining.
A few things she's mentioned lately:
I'm thankful for these things too!
Tonight I was in my room while the girls started dinner. I was getting ready for book club so M told me she would pray for dinner while I was in my room. Shortly thereafter, I listened as she stopped praying numerous times to yell at Lulu for "interrupting" her prayer. I tried to explain that she was trying to help and M got even more annoyed that I would imply that she needed help! :) So, finally, M, the smart girl that she is, said a prayer as fast as she could before Lulu could start chiming in! :)