Getting dressed in the dark is generally considered a bad idea. When presenting ourselves to the outside world, we like to have some visual feedback so we know what other people are seeing. Likewise, as young children learning to talk, we rely on auditory feedback--we need to hear ourselves speak. We continue to use this feedback, and adjust our talking accordingly, even as fully fluent adults. But at a certain stage of development, we may learn by not listening to ourselves at all.