
the "uh oh" sound is a natural corella vocalisation, mine does it as well and it so incredibly cute. I say it back to mine when he says it.
I am currently attempting to curb his excessive screaming. I have been away at college all week and left my partner in charge. Big mistake :/
Everytime the corella screamed he went over to it and either talked to it or misted it with the water bottle. Now it thinks scream = attention. Three days worth of reinforcing a horrible behaviour is going to take months to correct

I am so sad.
Too's are just like children, their ability to talk along with how quickly they begin to talk varies greatly. My first galah didn't say a word until he was about 12 months old and at the time I lost him he was only saying a few things.
Mana, my second galah is only 6 months old and already has a vocabulary that would rival a grey. Of course its the squeeky little galah voice, but she has literally blown me away. She will even mimic words she has never said or heard before immediately if she likes the sound of them. Like you I wasn't fussed either way if my birds talked, but I am amazed she is so brilliant.
My corella (BE2) is about 12-14 weeks and is saying a few things not very well. "Whatcha doin" "Hello" etc. All the simple things. He is now also picking up "whatcha talkin bout".
I will be glad once he has settled in and dialled back the screaming. He makes a sound I have never heard a corella make before...
[ame=http://www.youtube.com/watch?v=i_ys6CX4NrE]Baby corella wants out - YouTube[/ame]
Ever heard yours make this sound? He was handreared and weaned in a cage next to a black cockatoo... the sound he makes sounds to me like a corella trying to sound like a black cockatoo. It lacks the high pitched quavering of a normal corella call. Its interesting, but its not what I was prepared for and it makes me anxious. We have corellas in the area who call all the time so I figured no one would notice my corella. But because my corella doesnt sound like a corella I am getting nervous the neighbours will complain. I mean, the one to our left complained because my partner mowed a 4 inch strip over the property line on his lawn

And by complain... I mean he jumped on top of the fence and YELLED and threatened my partner.