Parrot and shopkeeper-Funny Riddle

Riddle 
A pet shop owner had a parrot with a sign on its cage that said Parrot repeats everything it hears. Davey 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?

    Answer: The parrot was deaf.