The Reason For Higher Price

A person went to buy parrot. He saw a parrot with a label saying: This parrot can speak two languages, price 200 Yuan.  He came along with another parrot nearby with its label: This parrot speaks four languages, price 400 Yuan.

Which one should I buy? The man hesitated, both are very cute. The man walked up and down, could not decide.

He suddenly found an old, toothless parrot with scattered fur. However it was priced as high as 800 Yuan. The man was very astonished, talked to the shopkeeper,
“So the parrot would say that 8 languages?”

The shopkeeper shook his head.

The man felt very strange,
“Why an old, ugly, useless would cost higher?”

The shopkeeper answered,
“It is because the other two parrots call this parrot boss.”