movie quote mad

So I have this quote stuck in my head, and I can't remember the movie. This is probably too vague to be useful, but:

A British kid, I'm pretty sure a little girl, is being hustled out of a room or being told not to talk to someone that her guardians are alarmed by.

Kid says, "I liked her! (or him) She (or he) talked about things!" Very clipped accent:

I LOIKED her! She taulked about Things!

The 'someone' is lovably eccentric and of no real danger.

It could also be from tv?

Aaaaaaaaaargh. Pretty sure it's not the Harry Potters. Going nuts trying to think about other movies or shows where this all happened. Argh!

Anyone have the vaguest clue what I'm on about?