If you have a shrill, grating, or brassy voice, which stems from tension in the throat and jaw, practice sounds that can be resonated in the chest for instance “alone, all alone by lowering your voice as if you are talking to a child.
If you have a flat toneless voice, which comes through the back of your nose, then move your tongue forward when you speak and your voice will emerge with clarity.
If your speech is slurred and inaudible, open your mouth wide while speaking and practice some tongue twisters like “Peter piper picked a peck of pickled peppers.”
If your voice is labored and weak, it is your diaphragm that is really weak. If you tend to talk quickly, then control your speed and try to take gradual leisure pauses whenever sense permits.
Following exercises will help develop your voice quality.
Lie flat on your back and stretch your arms straight up over your head with hands touching the floor. Inhale slowly and count 5, then hold the breath again for 5 counts trying to relax your body. Now let the air out in whisper (sh-h-hh) still counting 5. Wait for a while before repeating this exercise. Gradually increase the counts from 5 on intake, hold, outgo, hold.
Stand in front of a mirror, open your mouth wide and drop your jaw on to your chest. Then place the tip of your tongue first on the gum ridge behind upper teeth and then bring it down quickly to touch the back of the two middle lower teeth. Repeat this up and down movement until it works like a precision instrument.
Look in the mirror and repeat numbers for 5 minutes. Do not be lip lazy. Say the numbers energetically and clearly.
With your teeth clenched firmly, read a few sentences slowly at first and then rapidly. Start at the lowest note that you are able to and end with the highest.
Sit or stand naturally and practice whispering and shouting of some words alternatively. Whispering teaches studied control and proper pronunciation making your voice colorful and listening to, no matter how softly you speak. Shouting exercises your vocal cords and develops flexible throat muscles.