Oh, I found a book of those in the library a while ago because I wanted to practice solving them. You probably know all of these already, but...

[There's a moment of silence on his end while he hunts around for the book.]

A petshop owner had a parrot with a sign on its cage that said "Parrot repeats everything it hears." A young man bought the parrot and for two weeks he spoke to it and it didn't say a word. He returned the parrot but the shopkeeper said he never lied about the parrot. How can this be?