Another tremendous benefit of breathing with the support of your diaphragm is in the control of your nervousness in public speaking. There is nothing better that you can do physically than to allow your breathing to take control of your nervous jitters and put them to good use.
Nervousness can be either a nightmare or a blessing. When you allow it to work for you and not against you, you will benefit from the ‘fight’ response of nervousness in which your level of awareness will intensify, your sight will become sharper, and your perception of pain will be diminished. And this is exactly what you need if you want to be at your best when addressing an audience.
While breathing with the support of your diaphragm can have a tremendous effect on your speaking (& singing) voice as well as your presentation skills, it can also change your life in other respects because it is the most important thing you can do to eliminate stress in your life. Imagine something as simple as a diaphragmatic breath improving your life, both professionally and personally.