Why do parrots copy human speech?

In the wild, parrots learn calls from other birds and use shared sounds to identify flock members and strengthen social bonds. A pet parrot without other parrots treats its owners as its flock and copies the sounds it hears most. Parrots don't have vocal cords; they make sounds with the syrinx at the base of the windpipe and shape them with a muscular tongue. Some, like Alex, the African grey studied by Irene Pepperberg for 30 years, learned to use words meaningfully to name objects, colours and numbers. A budgerigar called Puck holds the Guinness World Record for the largest vocabulary of any bird, at 1,728 words.