But 2,400 years ago, Aristotle, the world's greatest authority on the subject, described it a little differently. In public or private, he taught, we speak for one reason: to persuade.
That can be challenging, because many of us suffer from speech anxiety. Probably because we've never been trained to think strategically about communication, despite the fact that it's one of the most critical skills in life.
According to Aristotle's teaching on persuasion, the art of eloquence is explained in terms that have nothing to do with conquering anxiety or learning to be confident, but rather with learning how people listen to us.
Here's what the Greek philosopher believed the most persuasive people do:
For most people, speech preparation entails endless hours obsessing over what people will think (e.g. "What if I fail?" "What if people think I'm dumb?").
Aristotle's advice? Cut it out. Focus instead on the people you're addressing.
Begin by asking yourself: Who will be listening? How many of them will there be? How old are they? What race and gender? What do they know about you and your topic? Why are they gathering to listen to you? How can you help them?
Before you begin writing, think about the purpose of your talk. Are you seeking to entertain, inform or inspire?
Next, express it as a specific goal in a single sentence: As a result of my presentation, I want them to know [X], and do [Y] as a result of my talk.
By aiming your remarks at the literal, concrete audience members, and by sticking to your purpose, you will eliminate a tremendous degree of free-floating anxiety.
In your mind, the subject of your talk is quarterly sales, company policy or your amazing new invention. Your audience, however, is focused on an entirely different topic — their happiness.
Aristotle listed a number of things that make people happy: Health, family, wealth, status and so on. Your success as a speaker, regardless of subject, depends on demonstrating to your audience that you're not just prattling away; you're talking to them, for their benefit.
Let's say you're pitching a financial product. You know that it's awesome. The numbers prove it. But what's going to make your audience happier? A lengthy diatribe about numbers, or an explanation of how these numbers will make their life better?
The point, as always, is that every element of your presentation should demonstrate your awareness of what they care about.
Whether you share much or little, your audience's decision to accept your words and ideas depends upon how credible they find you to be. "When speakers behave inappropriately," wrote Aristotle, "their credibility is questioned — even when they speak the truth."
It's intuitive that awkward body language or inappropriate clothing will distract people from your message, but instead of worrying about what not to do, train your attention toward the myriad of ways you can frame your presentation in the cognitive universe of your audience.
If your audience uses the metric system, don't talk in terms of inches. If you're from rural Illinois, for example, and you're pitching a medical cure for a dire disease to skeptical doctors and academics from Shanghai, talk about victims of the disease who come from Shanghai.
Every aspect of your presentation, including timing, humor, word-choices, metaphors and statistics, must mean the same thing to them as they mean to you.
John Bowe is a speech trainer, award-winning journalist, and author of "I Have Something to Say: Mastering the Art of Public Speaking in an Age of Disconnection." He has contributed to The New Yorker, The New York Times Magazine, GQ, McSweeney's, This American Life, and many others. Follow him on LinkedIn.