What other verbal techniques convey passion? Oddly enough, perhaps, rhetorical elegance on more formal or important occasions can convey emotion when it isn’t merely pompous.

Two main techniques, the rhetorical rule of threes and (appropriate) repetition, are the most powerful ways to convey emotion through rhetoric.  Let’s look at Martin Luther King Jr. giving what many believe was the most eloquent speech of the previous century at the Washington Mall on August 23, 1963.

First is the use of repetition to create passion:

I say to you today, my friends, that in spite of the difficulties and frustrations of the moment I still have a dream. It is a dream deeply rooted in the American dream.

I have a dream today.

There’s a real art to repetition. How do you manage it so that it doesn’t sound simple-minded but rather, as in this case, creates a crescendo of emotion that builds with each reaffirmation of the phrase, “I have a dream”?

The key is the phrase that’s repeated. It has to be able to bear the weight, and the words have to be affirmative, simple, and evocative. In King’s case, the words were perfect. But it’s not easy to find the right ones. The political world is full of repetitive phrasing and chanting of key phrases that the speaker begins and the audience takes over, but most of them are quickly forgotten.

The rule of three plays magnificently at the end of the speech, when King invokes a spiritual and brings the audience to its feet:

When we let freedom ring, when we let it ring from every village and every hamlet, from every state and every city, we will be able to speed up that day when all of God’s children, black men and white men, Jews and Gentiles, Protestants and Catholics, will be able to join hands and sing in the words of the old Negro spiritual, “Free at last!  Free at last!  Thank God Almighty, we are free at last!” 

There are actually two sets of threes here: the groupings of black and white, Jews and Gentiles, and Protestants and Catholics, as well as the final triumphant, “ Free at last! ”

And there are further subtleties. By giving us two groups of two — every village and every hamlet, and every state and every city — King creates in us a need to have the completion of a group of three. And of course he balances the two sets of groups perfectly.  It’s an amazing performance.

Perhaps you’re thinking, Well, that was easy for Reverend King. He was a great speaker and had time to prepare. But how can I achieve that kind of rhetorical passion in my communications, which are mostly off the cuff?  You may be astonished to find out that the second half of King’s speech, where these quotes come from, was ad-libbed.

What is it about groups of three that heighten emotion and create passion? Why do we respond so powerfully to them? It’s a mystery – something psychological.  Some say it has to do with religious symbolism, since there are groups of three in most major religions, but that may be putting the cart before the horse: the religions may have settled on groups of threes for the same psychological reasons that everyone else finds them powerful. Whatever the reason, we find something complete and satisfying in a group of three, like a three-legged stool that can stand firmly on uneven ground, and thus you should use them in your communications when you’re striving to convey passion.

Next time I’ll talk about using body language to convey emotion.  I’ll be speaking live about how to use both content and body language next week at the Public Words Speaker Forum 2010 in Boston.  Join us!