If this is one of the birds you are referring to inanother post that came from a Sanctuary, how long was he kept there? Birds learn to talk because they want to mimic us and they want our attention. They usually learn to talk from repetition.
Take for example my Eclectus Mac: He came to me second hand and one day, he just started saying "Want some fresh water". Now, this is the phrase that I always use when I get his water dish out of his cage. I would say, "You want so fresh water". I said this at least 5 times a day when I would change out his water and he picked it up. So now when I open up his cage in the morning, this is one of the things he says to me.
The same thing goes with his new game, which is Peek a Boo. He started saying Peek a Boo after I played this game with him for a week or so. But the other day he also picked up "Peek a Boo, I see you", which surprised my wife. But he will drive you nuts with "Peek a Boo" because he will say this at least a hundred times a day umtil I play the game with him. He's like a broken record. By the way, my wife thanks me all the time for teaching him Peek a Boo. I always respond that he could always start screaming. She likes peek a boo a lot better.