You can make educated guesses about audience demographics and attitudes.
If you can't get information in any other way, you will have to make educates guesses based on such indirect information as the general makeup of the people who live in a specific community and belong to a group like this or the kindsof people who are likely to attend the event or occasion. Suppose, for example, that you are asked by a nonprofit group you support to give a speech on volunteer opportunities with this charity to a meeting of high school guidance counselors who oversee community service projects for students. You can infer a number of things about audience member. First, all will be college-educated high school counselors from your city. They will all speak English. There are likely to be more women than men, and their ethnic backgrounds can be assumed to be similar to that of your community. They will be interested in your topic, but their knowledge of the specific opportunities at your agency will vary.