Hey Professor! Can You Teach Me to Sign?

My dad came over one evening to watch the little guy so I could leave for work. Next thing I know, out he comes from my bedroom, sporting one of my few purses over his shoulder. The little hand comes up and he says,
"Papa, you can go home now. I'm going to work."

"You're what?!"

"I said, I'm going to work. I got a job."

"You've got a job?"

(Exasperated) "Yes, Papa, I got a job."

"Well, where do you work?"

"At Purdue."

"You work at Purdue? What do you do at Purdue?"

(gestures randomly) "I signing at Purdue."

"You do?!"

"Yes, like Mommy do."

"Well, will you teach Papa some signs?"

"Umm, no, you take my class at Purdue." (trying to make a buck already)

"Please, just one sign?"

(sighs) "Ok, just one. (signs "grandpa") "There, one sign, that's your name. It means Papa."