"What is the most important thing to remember when you get up to give a speech?" Here are a few common answers.
"Have lots of slides, so they won't be looking at me all the time."
"Don't forget my notes."
"Wear comfortable shoes."
"Make sure they can hear me."
There are probably as many answers as there are public speakers. Here's mine: Most important? That the audience hears me and understands what I'm saying.
The primary vehicle we use to make sure they understand us is, naturally, our voice. How we feel about giving the speech will influence how we sound when we actually begin to talk.