Well, Now You Know.

The "ch, ch, ch, ah, ah, ah" sound in the Friday the 13th film scores is actually supposed to be the beginnings of the word "kill" and the word "mommy," according to composer Harry Manfredini who started the whole thing in the first place. You see, because Jason's mother was the killer in the first film. Which is treated as though it's a revelation in VH-1's series even though I'd think Scream kinda blew the doors off that one. And because there's a scene in Friday the 13th in which Jason's mom crazily speaks to herself "as" her son, saying "Kill her, Mommy! Kill her!" So you see it all makes perfect sense.

May the Force be with you, Jason Vorhees.