I've begun using the rather crude, but effective, line about linguistics from one of my favorite movies. I use it every time somebody forgets how to use "effect" and "affect," or perhaps "to," "two," and "two."
Oh, and my personal favorite: Less is qualitative, fewer is quantitative.
Anyway, since you're all wondering:
"ENGLISH, &$@#^* %@&$*#! Do you speak it?!"