Marni's favorite phrase right now seems to be "But I want to".
This usually occurs when she wants to do something that we don't want her to do. For example, if she wants to go upstairs and we say no, the next thing you will hear from her (over and over) is "I want to".
I want to!
I want to!
I want to!
I want to!
Over and over again until she bursts into tears.