Where did this quotation in "The Last Emperor" come from?

As Peter O’Toole is first tutoring the young Pu Yi, he explains the importance of grammar: “If you cannot say what you mean, you will never mean what you say, and a gentleman always means what he says.”

Was this written just for the movie, or does it have a historical context?

It does seem to be related to this exchange from Alice in Wonderland:

And then there’s also Humpty Dumpty in Through the Looking Glasson the meaning of “meaning”.

Or from Dr. Seusse?

this reminds me of Chompsky…

booklyn, welcome to SDMB.

Thanks for mentioning that one. I had misremembered it as “Sweet green dreams sleep furiously.” (But I first learned about it a little closer to the time that Chomsky came up with it.) Now it makes less sense – which is a good thing, of course.

I noticed another response of yours elsewhere. Hope you hang around.