Public speaking is the number one fear of the majority of adults-it even ranks higher than death! The result is that dreams of this sort are common. Rarely are they nightmares, but rather dreams of scrutiny and overcoming. Often the occasion of the speaking or the audience members will suggest something to you about an area of your life where people are looking too closely for your comfort.
Another version of this is the public speaking dream where the topic or attire is totally inappropriate for the dreamer's context. This dream is similar to the nudity dream in that exposure and inadequacy are themes in the dream. The dream may be an attempt to expose a weakness that you are covering up.
Was the nature of your public appearance absurd, or did it somehow fit logically with your waking life?
Did you feel a sense of high anxiety during the situation, or were you calm and forthright?