"...you're mighty preachy and you gonna preach your neck (right into a hangman's noose.)" The Sheriff of Nottingham is not happy with Friar Tuck's confrontational comments about taxes and the poor.
This is a Milt Kahl scene, and these drawings were photocopied before a clean up artist would erase some of the construction lines and eliminate extraneous ones, on the original sheets.
But these animation key drawings are pure Milt. The back of the head leads the motion, and when the head arrives at the high position, Milt goes crazy with with the character's dialogue. The word "mighty" is about to come up, and for the middle vowel he just about breaks the jaw for an extremely large open mouth shape (drawing 53).
No other animator at Disney would take it this far. There are people who love this kind of stuff, others resent it. (Ollie Johnston wasn't crazy about Milt's oversized mouth shapes).
To me this works when applied only occasionally to a loud, strong vowel. If you only use big mouth shapes in your dialogue animation, the character will end up grimacing, instead of talking naturally.