How should supporting materials be used in a speech according to the chapter?

Supporting materials should be used to illustrate or prove the main points of a speech. They can include personal experiences and credible sources, and are essential for providing evidence and lending credibility to the speaker's message.

In a speech, supporting materials serve to illustrate or substantiate the main points being made. These materials can encompass a wide range of information, from personal anecdotes to various credible sources. The use of well-researched supporting materials is crucial for providing evidence for assertions and enhancing the overall credibility of the speaker's message.