Princess

We had a very verbal girl over to our house on Friday. She's really just three months older than big T, but is leaps and bounds ahead of him in the talking game.
She was very quiet at first, and so I chattered on, telling her about the house, about T, about M, about supper etc. Children need to learn very basic things that we take for granted knowing, so I told her that T was a boy and M was a girl.
A few minutes later, I decided it was time for her to finally start talking to us. I thought direct questioning would be the way to go about this.
I said, "Do you know his name?", and I pointed at T.
She giggled and mumbled something, and then laughed hysterically.
"What?", I said.
She laughed even more. And then she pointed at him and said loudly, and audibly, "Princess!", and hysterically laughed again.
I didn't even know what to say.