The voice may be the most popular and the most misunderstood instrument on the face of the Earth. You can’t just pick up a guitar and play a song without first taking a few lessons. But you can sing a song without ever taking voice lessons. Of course, most people aren’t very good singers. Just like any other instrument, there’s a technique to singing that you have to learn before you can sound good. However, unlike other instruments, the technique behind singing lies almost entirely in human physiology.