In this speech, which way does the speaker use in the opening part of speech? The human voice: It ’ s the instrument we all play. It ’ s the most powerful sound in the world, probably. It ’ s the only one that can start a war or say “ I love you. ” And yet many people have the experience that when they speak, people don ’ t listen to them. And why is that? How can we speak powerfully to make change in the world?