Many people wonder whether their conversational tone of voice is too high or too low - each person's vocal pitch is different. It is impossible to change your natural tone of voice - there are ways, however, to alter your voice if you are speaking at an unnatural pitch. Once you have determined your natural pitch, practicing in private is the key method to successfully reaching your proper conversational voice pitch.
Hum the song "Happy Birthday" while recording it with a tape recorder.
Play the tape recorder back to yourself and determine the medium pitch at which you sing most of the song.
Compare this pitch to your normal tone of voice to determine if your speaking voice is too high or too low. Note that if the two pitches match, your voice is already at its natural pitch.
Relax your muscles - tighter muscles will raise your tone of voice.
Conceptualise internally that you are projecting your voice from your chest, instead of your head. Notice that this creates a deeper sounding pitch.
Practice speaking in private with your hand on top of your chest. Speak so that you can feel your chest vibrating.
Work consciously during conversations to remember your natural pitch - practice in private will more effectively ingrain this vocal tone in your mind until it becomes second nature.
Continue humming the "Happy Birthday" song in private. Switch back and forth between humming and speaking (normal sentences) to level your speaking tone with your humming tone.
Add the acknowledgement "mm-hmm" into regular conversations - after correlating your hums with your words so often in private, this will remind yourself to match the two in public as well.
Keep practicing this drill until your tone of voice naturally matches your natural pitch.
If your voice is already at its natural pitch, it cannot be changed.
Sometimes extremely low- or high-pitched voices are the sign of a physical problem. Check with your doctor if you feel this might be the case with you.