@Thomas,
Well, the boy definitely understands presents.
Grandpa won't be joining us on Christmas Day, so he dropped off his presents early. Buddy waited until Grandpa left, but then immediately went and started trying to tear them open. He didn't even wait to find out if they were for him!
About 10 months ago, T picked up some birthday cupcakes from a bakery next to the girls' dance studio. The boy keeps trying to go in, and T couldn't figure out why. Finally, yesterday, he pushes on the door and says, "cu' cake!"
And he's started recognizing Santa. Santa ornaments, Santa little people, Santa decorations, he'll point and shout, "Ho -ho!"