Thank you for your question.
I know almost all of us have some nervousness just before we speak. The responsibility that comes with the opportunity should make that true for everyone.
There are a few different ways to deal with the nervousness and the shaking that comes from it into the voice and gestures.
1. “Speak through it” and ignore it until it goes away. Practice, practice and more practice. Joining groups that will give you “stage time” like being in a Toastmaster club, will allow you to overcome a great deal of the unwarranted anxiety. But will not entirely remove it.
2. “Bottle it”. Allow the energy of being nervous to come through in your presentation as enthusiasm. Containing the energy and using it for vocal and gestural expression will greatly enliven a presentation.
3. Speaking from the heart. (My favorite) when you speak what you have lived, what you know without thinking about there is a sense of conversation rather than lecture. You know the content backward and forward so you are unlikely to leave anything out. Your emotional state as you present will match the emotions you experienced when you learned the lesson or information or lived through the events of the story. This is the reason I teach story telling as a primary means of communication. Adding a call to action or point at the end of each story is extremely effective for connecting with the audience as well.
I am concerned for anyone who reaches a point where they have no “fear and awe” of the role, authority, responsibility and power of influence they have when they speak. To ignore that is to take too lightly the level of accountability that God holds teachers too.
I hope this helps.