Whilst making presentations my voice changes and becomes squeaky. Is there any way to control the voice? I have been told that I make my presentation very fast.
I do not use the word “control” as it tends to create tension. There are, however, ways to assist the voice.
In your case, working with the breath will be the single most important tool. You need to make sure the lowest ribs are engaged and stay open. You can find this work by making a small, silent grunt (as though you are about to lift a heavy object). When you inhale, these ribs should expand and the abdominals should release. Do not push the abdominals out or pull them in. Just allow them to respond to the breath.
Keep your breastbone lifted but not hyper-extended. If you lift your arms above your head you will feel the upper body lift out of the hips. Keep this lift when you lower the arms and release the shoulders. You will find that you could actually make the breast bone go a little higher but that would be too much because it would create a pinch or compression in the back.
Think of sounding a warm, open “OH” sound on a low pitch. Feel the vibration in your chest. Each time you inhale, imagine this “OH” sound and speak the sentence into that preparation.
Walk slowly around the room, feeling your breathing and heart rate slow to the pace of your step. Then speak slowly at the same pace. When you come to stand still, imagine this slow, easy movement while you speak.
All of these suggestions will not only help the voice — they also reverse the symptoms of the “fight or flight response.” They lower blood pressure, slow the heart and respiration rates, and stimulate the brain to produce positive endorphins rather than adrenalin.
This is in no way a comprehensive approach, but it will give you some things to play with until you find a coach.