Your most valuable asset as a speaker is your voice. Effective speakers vary the pitch and inflection of their voice for emphasis. Think about all the monotone lectures you had in college. Remember how boring they were? One reason was that the professor never varied his or her tone of voice. Big points melded with small points into some kind of tasteless stew of ideas that never boiled, never simmered, just remained lukewarm. And was forgettable.
But with practice, you can move to the head of your class by putting some zip and zest into your voice. Here's how.
Give voice to your voice. Practice using rising and falling inflections for meaning as well as for questions. Inflection is a form of audio punctuation. Use it!
Hear your message. Record yourself speaking. After you get over the hurdle of what your voice actually sounds like (trust me, everyone hates the sound of his or her own voice), listen to what you are saying. Ask yourself:
How am I using inflection?
Do I sound credible?
Would I buy from this guy?
This final question applies to everyone, not just salespeople. As presenters, all of us are pitching something, so we need to ask whether the audience is buying it, i.e., is receptive to the message. When speaking about Sundance or his commitment to the environment, Robert Redford employs his actor's ability to reflect his conviction through his voice. You recognize his sincerity in an instant.