What i did was i clipped my cockatiels flight feathers and recorded his name on my cell.Then i put my cockatiel in his cage (where he feels comfortable) and put my cell phone in there with the recording of his name.It kept replaying his name over and over......Till the point when he started chirping the rhythm of his name and soon enough after a couple of days he was able to say his name.
TIP (down below if you are having trouble teaching you bird)
Try 1or 2 syllable names for your bird.They have a much easier time saying there name if it is 1 or 2 syllables long. That is just a tip i am giving you.