Definitions. A definition helps your audience understand what you are talking about by translating your topic into words your listeners will understand. It helps to ensure that speaker and listeners are talking about the same thing. Audience analysis should help you determine whether you need to provide definitions in your speech. As a general rule, you should provide definitions for any technical terms that are unfamiliar to your audience the first time you use them. In her informative speech at Vanderbilt on genetic testing, Ashlie McMillan first offered a technical definition: “According to ‘The Genetic Revolution,’ an article in Scientific Magazine, genetic testing ‘is corelating the inheritance of a distinctive segment of DNA, a marker localizing the mutant gene on a DNA strand which composes our chromosomes.” Noting the puzzled look on her listeners’ faces, Ashlie then said, “I found that a little confusing too, so I tried to put it in my own words: Genetic testing is simply looking at people’s DNA to find a pattern of a mutant gene. That’s basically what it is.”
Definitions can be persuasive as well as informative. A persuasive definition reflects your way of looking at a controversial subject. It presents your perspective in such a way that your listeners will want to share it. A persuasive definition usually puts the subject in an emotional context. In a speech on domestic violence against women Donna Shalala, U.S. Secretary of Health and Human Services, provided the following persuasive definition of domestic violence: “Domestic violence is terrorism. Terrorism in the home. And that is what we should call it.”