Properly Control Your Air Supply. For best results in the use of your voice, you need an adequate supply of air along with proper breath control. Without these, your voice may sound weak, and your delivery may be choppy.

The largest part of the lungs is not at the top of the chest; this area merely appears larger because of the shoulder bones. Rather, the lungs are widest just above the diaphragm. Attached to the lower ribs, the diaphragm separates the chest from the abdominal cavity.

If you fill only the top portion of your lungs when you inhale, you will soon be out of breath. Your voice will lack power, and you will tire easily. To breathe properly, you need to sit or stand straight and hold your shoulders back. Make a conscious effort to avoid expanding only the upper part of your chest when you inhale to speak. Fill the lower part of your lungs first. When this part fills, the lower part of your rib cage will expand sideways. At the same time, the diaphragm will move down, gently displacing the stomach and the intestines, so that you feel the pressure of your belt or other clothing on your abdomen. But the lungs are not down there; they are within the rib cage. To test yourself, place one hand on each side of the lower part of your rib cage. Now breathe deeply. If you are breathing properly, you will not be sucking in your belly and raising your shoulders. Instead, you will feel the ribs move slightly up and out.

Next, work on the outflow of air. Do not waste the supply by letting it escape with a rush. Expel it gradually. Do not try to control it by tightening your throat. That would soon result in a voice that sounded strained or abnormally high-pitched. Pressure from the abdominal muscles and from the intercostal muscles (between the ribs) expels the air, while the diaphragm influences how quickly it is expelled.

Just as a runner trains for a race, so a speaker can develop proper breath control by exercise. Stand erect with shoulders back, breathe so as to fill the lower part of the lungs, and gradually exhale while slowly and smoothly counting as high as you can on a single breath. Then practice reading aloud while breathing in the same manner.