Overheard this morning in the kitchen:

The Refrigerator is open.

Grayson: “Goguh!”

Daddy: “You want some yogurt?”

Grayson: “Uh-huh”

Daddy: “Okay, let me get it”

As soon as Daddy touches the yogurt, Grayson says: “Yes” just perfectly.

Daddy: “Can you say ‘yes?'”

Grayson: “Yes”

After getting the yogurt, Grayson says “Mmmmmmm” as he walks away.

So, yes, Grayson can now say “Yes” perfectly.