There's an "everybody talk at once" mode where they will chatter, squack and cheep all at the same time. It's usually while we're on the phone and/or needing to hear the other party.
I came across Elizabeth Vaughn's series of articles on Communication & Social Behavior in Cockatiels. She's a counsellor by profession and she has a keen sense of behavioural observation. It sounds like she also has a pretty big flock in which she tries to let the birds have a community that reflects their natural lifestyle as closely as possible.
This paragraph, from Part I - The Cock's Song, stood out to me:
"Although hens do express themselves vocally, for the most part they do no [sic] develop song. I came across one exception however. A young cinnamon who was about six months of age when I acquired her, learned to imitate the cocks' songs very well indeed. So well, in fact, that I was sure she was a cock even though she failed to manifest any of the other male characteristics. As long as her singing continued, she was shunned by cock and hen alike. When she learned that her exceptional abilities were getting her nowhere, she silenced herself, and soon became accepted into the community..."
And sometimes, I really don't feel so bad about raising our two in an unnatural environment. Then again, sometimes, I just want off this planet.