Ahhhh a bird question....now this is my field
Cockatiels are generaly quiet but can be noisey at times...they need about 2-3 hours of handling time a day...give or take...Make sure if you want to be able to handle it, you get a "handfed cockatiel" they have much stronger bonds to humans as they were raisssed by human parents instead of theirs. Although they might have a higer price range its definitly worth it!!! Most people dont know this but try to keep Mirrors out of the cage, this will cut down the talking as well, birds think its another mate and try to sing to it....Mirrors also make birds sick...they get too attached to them and they can actully get depressed...freaky eh? If your worried about noise....try your best to get a female...its about $50 blood test to sex a bird through Health Gene... they cut the nail too short so the quik bleeds, put it on a card and send it away, your results should be back in a week or two. Males sing more to intise mates...and are also the better talkers. If you dont want to spend the money on blood tests...females have lighter colouration on the cheeks and when they are older, on the underside of the tail if you look closly the tail feathers will be stipped and if its male they will be solid.
Whatever you do...try to stay away from circular cages! Bad bad bad idea...It can make a bird motion sick, they need a corner to feel safe in!
Hope i help if they're any more questions let me know