What makes you apprehensive about public speaking?

In the book, it mentions the sources of speech anxiety which are uncertainty about your role as a speaker, your speaking abilities, your ideas, the audience’s response, the setting, technology, and evaluation. There are three of these that make me apprehensive about public speaking. First, is the uncertainty of my speaking abilities mostly because when I get nervous my voice is either really low or really “quivery” which can be very embarrassing. Second, is the uncertainty about my ideas because I worry I don’t know enough about what I am talking about. And lastly, my uncertainty about the audiences response. This goes with the second one for me and the reason that is, is I worry about if I know enough and then it makes me stress about what the audience think about what I am saying and usually what comes to mind are pretty negative, something I am working on. The book also mentions to stay positive, so that is something ill try next time.