They both understand a lot more than they let on.
And they are certainly stubborn creatures that crave attention and variety and are happy to let you know when you have not provided it. Rather like people actually.
I am reading about parrots, it is my new mini-obsession. I think I need to write a story with an African Grey having a role. Smart smart birds. If only their tweet wasn't quite so shrill.
The talkative Alex is an amazing story. Could think on the level of a 5 year old child. 150 word vocabulary.