Can cockatiel talk

Yes, cockatiels can talk. I have a friend who will screach "pretty bird" until he gets attention from someone. It may take a while but if you recite a phrase enough (and beware anybody that uses foul language) they will eventually learn to talk.

It should be noted that cockatiels do not actually talk. They mimic sounds, including human speech, but are incapable of forming intelligent sentences or associations with the Words they seem to say.