Fellow speaker,
A "callback" is when you use something in your speech that occurred previously, either in your speech or outside of your speech. A callback to something outside your speech lets the audience experience a speech customized just for them. So now and then use a call back in your speech to an outside event. For example, if the speaker before you was telling about the importance of a story and you are talking about stories, you could say, "As you have already heard, stories are very important in your speech."
Calling,
Tim
