I am foreign so I might very well be wrong about teach and learn but

[Gorionine]

"That will learn them"? Should it not be "That will teach them"?

yes it should be that will teach them, but that'll larn'em' (said, in my grandad's case, in a thick Norfolk accent) is colloquial. I would say 'that'll larn'em' knowing it was wrong in an informal situation.

Thanks, that'll larn me for being so pedant!