Many people have naturally nasal voices. This can be due to genetics, physical makeup or a habit resulting in a voice that is projected up through the sinuses. A nasal voice is very high-pitched and tinny and has a grating sound. Through exercises, a person can learn how to make his voice flow through more natural sound channels in the body.
Stand in an upright and relaxed position and place your thumbs on your belly button. Breathe in deeply while staying upright. Imagine your breath going down into your body to your thumbs and below. Use your thumbs as a tactile gauge to let you know that your breath is dropping in.
Exhale through your mouth. As you do so, relax your jaw as much as you can. Keep your throat muscles relaxed. Warm your hands by rubbing them together and gently smooth them down your throat to keep it loose and relaxed as you exhale. Practice deep breathing in this manner every day, and remind yourself to breath deeply while talking.
Drop your jaw low as you speak and imagine the words flowing out through the bottom of your mouth. The more relaxed your jaw is, the more difficult it is to send the sound up through your nose. With each syllable, imagine your jaw dropping and the sound staying low in your mouth.
Clasp your hands together in front of you. Open your mouth, relax your jaw and gently shake your hands back and forth as you exhale on a neutral tone or sound. The shaking will relax your jaw and let the sound flow naturally.
Practice enunciation through tongue twisters and other vocal warm-ups such as repeating "Peggy Babcock" or "Toy Boats" over and over again. Over-enunciate the words to exaggerate the proper way of forming the syllables without nasal sound travel. If your exercises sound nasal, repeat the breath and jaw exercises and practice enunciation again.
Do the exercises on a regular basis for a long period of time to counteract nasality in everyday speech. If you start to avoid nasal sounds deliberately over time, however, it will eventually become second nature.
If you have long term problems with nasal speech that exercise does not correct, talk to your doctor. Some people have physical problems in their speech apparatuses that create nasal speech that only surgery can correct.