Hearing yourself speak

Cell phones differ from land line phones in that cell phones do not send your own voice back through your own ear as you speak. In noisy places, this results in people needlessly shouting into their cell phones in order to hear themselves speak, even though the cell microphone will pick them up fine at a lower voice. People find it psychologically unnerving to engage in a conversation where you cannot hear yourself as you speak, almost as if your words are disappearing out of your mouth. You need aural feedback that you've actually spoken something.