Of all the potential terrors humans face, "Studies show the number-one fear is speaking before a group," says communications expert Arch Lustberg.

"It's hard to believe, but more people have a greater fear of public speaking than of death, job loss, killer insect bites . . . you name it."

And testifying--whether it is before Congress or the local civic association--"is public speaking with a special, stressful twist," says the former Catholic University speech and drama professor who now teaches U.S. Chamber of Commerce workshops on the skills of testifying. Among his other credits: production of the 1972 Broadway musical "Don't Bother Me, I Can't Cope" and the late Sen. Everett M. Dirksen's 1966 Grammy Award-winning record album, "Gallant Men."

"Today, few local, state or federal bills or regulations are enacted without hearings," says Lustberg, 57. "But very few people who speak at those hearings have learned the skills of effectively delivering testimony.

"The typical scenario is the fellow who puts on his stuffy half-glasses and drones through pages of a text he's hardly looked at--and he expects people to pay attention to him. Someone who speaks his piece clearly and confidently--who's energetic, pleasant and sincere--has a tremendous advantage.

"Confrontation has become a favorite technique of legislators who want attention. You've also got to be prepared to deal with the consumer advocate or the reporter who asks a zinger like, 'Why does your company rape the land?' "

Many testifiers don't realize, he says, that their goal should be "to inform and persuade the officials and audience members who are unsure of their stand on the issue in question.

"The people in favor of your position are already convinced, and you're not going to change an opponent's mind in the time you've got to testify. So you should concentrate on the most important group--the people who haven't made up their minds."

Instead, people tend to concentrate their energies on supporters and detractors--often rising to their bait--and wind up turning off the crucial, undecided group.

"If you snap back at an obnoxious senator, 'We don't rape the land,' " says Lustberg, "you're repeating the negative buzzword. Listeners will now hear 'rape the land' twice, and that's what they'll remember and associate with you. Also, you're likely to screw up your face in a grimace that will look very nasty in freeze frame. Getting into an ugly argument presents a poor image to the people you're trying to win over."

Instead, he says, "Explain, as if to a dear friend, what it is that he or she doesn't understand. Take a deep breath and collect your thoughts, then explain how your company always leaves the land in better condition than you found it--if that's true.

"If it's not, then stress how important that product you take out of the land is to heating our homes or reducing American dependence on foreign oil. What you want is to come across as calm and reasonable. Not condescending, but nice."

"Love," proselytizes Lustberg, "can even beat Mike Wallace."

Of the four responses an audience may have to a speaker--like, dislike, neutral or (the worst) pity--"the only one that counts" in testifying, claims Lustberg, is the first.

"You're not going to get your message across unless they like you. That's why Ronald Reagan's our president. More people liked him than liked Jimmy Carter. When an audience likes you they'll wonder why that rotten reporter is digging at you. But if you get caught up in a shouting match they'll think you're a real jerk."

"Delivery," maintains Lustberg, pointing up a pragmatism which should not surprise Washingtonians, "is more important than content."

His "basic principles of communication":

1. Strive for an "easy, open facial expression."

2. Use body language to emphasize words.

3. Pause; take a moment for emphasis, to breathe and throw off stress.

4. Exercise eye contact.

Among pointers geared specifically to delivering testimony:

Pay attention to protocol. Thank the panel for the opportunity to speak, and introduce yourself briefly--unless someone else has already introduced you.

* Come prepared with two texts: one detailed, one abbreviated. Since time may be limited, be prepared to submit the full testimony and deliver a brief summary. In general, the text of the testimony shouldn't take longer than five minutes. "Vaudeville acts got 12 minutes. What gives us the ego to think we can captivate people for 45 minutes?"

* Learn everything you can in advance that is relevant about your audience. Know the names, pronunciation and titles of the people you're addressing.

* Pay attention.

* Generally, stay with the positive side of your case, unless you can demolish your opponent's case with logic and wit.

The best advice for testifiers, Lustberg says, is to "remember that communication is the transfer of an idea from one mind to another. Try to make each person in your audience think you are talking directly to them."

For more information on Arch Lustberg's Communicator Workshops, call the U.S. Chamber of Commerce, 463-5707.