HARVARD COMMENCEMENT guests, you are about to witness something remarkable. You may never again hear speeches as special as the ones you will hear today. Now I won't guarantee that the speakers' delivery will be especially skillful, their ideas especially trenchant or their wit especially sparkling. Hell, I won't even guarantee that they'll keep you awake.

But I will guarantee one thing: today's Commencement speakers wrote their own speeches, and submitted them to a grueling competition to boot. (OK, they had a little help from the expository writing director, too, but it's their work in essence.)

Even President Derek C. Bok writes his own material, even if he doesn't mean it 90 percent of the time.

The remarkable thing is that so few public figures ever speak their own words. "Ghostwriting," the polite term for plagiarism, has overtaken American public life.

The symptoms are everywhere. Sports stars who can't string together a grammatical sentence in a post-game interview show up on the covers of hardback autobiographies written "with" a ghostwriter (whose name appears in small print at the bottom).

Even reasonably intelligent people, such as Washington influence peddler Clark Clifford, no longer trouble themselves to write their own "memoirs."

During the Reagan administration, we learned that not only did a White House spokesman routinely invent quotes and attribute them to the President, but that America's chief executive could not say "It certainly is a pleasure to have you here" without looking at notecards.

Ghostwriting is so firmly implanted in public life that a politician who routinely wrote his own speeches--or better yet, spoke off the cuff--would become an instant national celebrity.

IT WASN'T ALWAYS this way. In the last century, American politicians were expected to "speechify" for hours on end, without benefit of speechwriters, teleprompters, or even notes. The great orators of the day--Webster, Clay and Calhoun--effortlesly infused their speeches with Biblical allegory and allusions to the classics.

Before the age of mass communications, a candidate could tour the country, delivering the same well-worn speech at every whistle stop, improving and embellishing it with every delivery. Today, a candidate is expected to produce a continuous fountain of new and original speeches--a difficult task even for someone who isn't busy courting PAC donations and dodging the ethics committee.

The advent of mass communications technology changed speechmaking in another way. Before mechanical reproduction, few reporters could truly record a speech verbatim; thus, the hesitations and minor lapses of grammar that characterize everyday speech were never seen by the newspaper audience.

At the same time tape recorders were capturing every word of speeches, rapid communication introduced the possibility that a fatal "gaffe" could, in a matter of hours, be disseminated across the entire country. More recently, the 30-second TV commercial placed a high premium on packing as much emotional impact into as few words as possible--something few people are capable of doing extemporaneously.

MASS COMMUNICATIONS technology meant the imperative of perfection--a perfection most easily achieved with speechwriters and teleprompters. But is there really anything wrong with a division of labor between the person who conceives the speech and the person who puts it into words?

In some ways, there isn't. There's no law of nature that says only gifted speakers can be good statesmen. Thomas Jefferson, for instance, never overcame his stuttering. Ghostwriting, then, could be seen as just a way of leveling the political playing field--allowing voters to choose on the basis of issues, not speaking ability.

On the other hand, there is a certain value to attaching words to the men and women who spoke them. Can you imagine learning that Daniel Webster or Winston Churchill had some 24-year-old Ivy. League weenie on the staff churning out lines like, "Liberty and union, one and inseparable, now and forever!" and "We have nothing to offer except blood, sweat and tears"?