My 9 year old has always been very serious and had a vocabulary beyond her years. She picks up phrases from all around her, and it was a constant source of amusement when she was little. This is her watching Americas' Got Talent. I think she was just turned five at the time.
Big girl: What on EARF? (it was a sort of Bollywood performance)
and later on: Are they knockin' your socks off? They're knockin' my socks off.