<span>Most human communication cannot be understood outside of the context in which it occurs</span>
Foreshadowing is when an author uses symbolism, an event, a small detail, or even a part of dialogue to be a warning or indication of a future event. An author might use this because they want to give the reader knowledge about a future event or to tease them.
He should focus on the main idea of what he is speaking about and have good details. He must have necessary words that will make the people better understand what he is talking about.