It doesn't make any difference how long your speech is. Unless you tune in your audience in the first 60 seconds, chances are they will tune you out.

Take the fellow who opens with: "On my way over to the club tonight, I ran into a bum who asked me for $49.50 for a cup of coffee. I told him he'd do much better if he asked for a quarter. He said, 'Do you think I'm going into the Ritz in these clothes?'" We know his purpose: to win his audience over with humor. His bit of humor, however, has no connection with his speech, "The Democrats' Dilemma". He has his audience laughing at the wrong time. Once you have an audience laughing it's hard to get them to switch to an entirely different train of thought. There's nothing wrong with humor in a speech as long as it has something to do with the purpose of the speech. To open a speech with humor just to be entertaining invites an almost sure "turnoff" for the remainder of the talk.

Q. Underline the sentence which states when humor can be used in a speech.