Out of the Mouths of Babes.

Me: Pick up the toys.
Preschooler: I don't know how.
ME: PICK.UP.THE.TOYS.
Preschooler: IF YOU DON'T KNOW HOW, YOU DON'T KNOW HOW!
His memory was jogged after he pushed the issue right up to the limit.

Not much comes out of the mouth of the Wild Thing except grunting that is accompanied by pointing. He brings his cup when he wants something to drink. If you don't get up and fill his glass then he will take it, put it in the kitchen, and position himself directly in front of you so his pointing/grunting can not be missed. He says MAAAA MAAAAAA when he's mad.
Thanks to the Preschooler, he shakes his fist when asked "you want a piece of me?"
I guess you could say he's into sign language.