I just ran accross a link that talks about conviction and our voice tonality and how it affects our presentation. This is worth watching. Notice how the way he says something affects the impact of what he says.
Overcome Fear of Public Speaking with Hypnotherapy
Are you tired of your heart racing every time you need to speak in front of others? Many people feel scared about public speaking (it’s one of the most common fears), but there's a solution that might fix your problem quickly! Hypnotherapy is a gentle way to...