Still Children?

[deckardcanine]

In comic strips, it’s common for the children not to talk
Like children all the time, and what they say is not a shock
To grown-ups in their world, who must expect them to be smart.
It’s not so common elsewhere; maybe that’s the strangest part.
Consider most TV shows, where the kids are rather plain,
Apart from those supposed to have extraordinary brains.
Just why do still cartoons give children more adult-like lines?
My best guess is they age much less in bodies than in minds.