My youngest was a late talker. She apparently knew how, but either didn't need to talk because her twin brother did it for her, or decided we were beneath her and had nothing to offer, conversationally.
She spent some time communicating in movie quotes when she was three. We had to be very careful what videos she was allowed to watch. When she told her brother "You'll never bring this family honor!" after seeing MuLan, she made him cry.

"I love it when you two impersonate earthlings."