The alien spoke gibberish.
The little monster thought this was hilarious!
He was laughing so hard he had tears in his eyes.
He never laughs out loud at the TV, he might smile sometimes, but never the full on giggle.
It was really hard to tell if he was laughing because the alien was talking funny, or if he was laughing because he finally found someone who spoke his language and it was the first joke he understood.
Whatever it was, baby giggles are an awesome way to start the day!