THE POTENTIAL for insult is infinite. That is the first lesson in learning Chinese. The teacher walks to the blackboard and writes in chalk the word "ma." Any carpet-bound 1-year-old can master that word, I say to myself. But in Chinese, things are rarely as simple as they seem. "Ma" can mean "mother," or it can mean "horse" or "hemp" or "to swear." It all depends on the tone or inflection with which the word is spoken. Here is an early warning that the best of intentions can spark an international incident.

The class is dumbfounded. My wife and I are scribbling in our notebooks, eyeing the clock for the next three hours and feeling like the victims of a cruel linguistic prank. During the break we wander the halls shellshocked, staggered by the unfamiliarity of it all. Weeks pass and the classshrinks from nine to a more intimate foursome. There is no one to hide behind.

"How hard can it be," I ask myself, "if a billion people already have it down pat?" That's one in four on the planet: as many as speak English, Spanish, French and German combined. It doesn't seem to help.

I am reminded that I have a tin ear. Between "Ja" and "Cha" is a world of sounds to which I am not yet privy. When called on in class, my tongue plays possum. The sounds I'm supposed to say remind me of childhood games -- whistling with a mouth full of saltines or reciting the Pledge of Allegiance with a jawbreaker roundly pressed against the palate.

Mandarin, the dialect I am wrestling with, has four tones. The first is spoken as if one were castrated, with a high- pitched sound. The second tone rises. I think of ing into the waters of Maine. The third tone dips and rises. The fourth is like the shuttlecock in badminton, struck midair and driven downward. Chinese is less like studying a language than learning to sing a cappella. Today I am pacing about the back yard with my cassette player slung on my belt and earphones to ears, mouthing singsong phrases. No doubt the neighbors think I'm mad. But in a matter of weeks I will be living in China and counting on these verbal melodies to find the men's room, commute to work, enumerate my aches and pains and spare myself the excesses of Chinese chefs.

I HAVE A LONG and checkered history with language. I was what was charitably called a classics major: Latin. That was a decision in part made for me by a French teacher whom I had tormented with my mutations of francais. There were, he reasoned, no Caesars left to wince at my corruption of amo, amas, amat. And I was reminded exiting his office that non omnia possumus omnes, by which Virgil meant: "We can't all do everything."

Later I would mangle Italian and get my first taste of the damage that can be done with a living language. Once, as the guest of honor at a Christmas dinner in Tuscany, I listened to the family matriarch tell a bizarre tale. At the end of her story, I tried to show my attentiveness. I took her hand in mine and, looking her in the eyes, directed my tongue to say the Italian word for "strange!" -- "Strano!" But the wires got crossed and I blurted out "Stronzo!" a vulgarity not worth translating.

Of course such things are mere child's play compared with what can be done with Chinese. After three months I have an armory of a thousand words, each one a short-fused rocket waiting to go off. With a twist of the tongue, a simple quarter note awry, each of those hard-won syllables can have a wholly unintended resonance. In the interest of world peace, I have taken it upon myself to avoid any conversations near the borders of Korea, Vietnam or the Soviet Union.

Orwell said, "The great enemy of clear language is insincerity." That's easy for him to say, speaking in English. I ask my Chinese teacher a simple question in Chinese, with all the sincerity in the world: "What does your father teach?" He answers with his father's name. It is as if a frame or two has been cut from the film. There is, of course, an explanation. The sound "jiao" spoken with a high pitch means "to teach." The same sound spoken with a martial tone, cudgeling the word as I have, means "to call" as in one's name.

So much sounds so alike. A classmate, speaking in her best Mandarin to a Chinese church group, intended to speak on "the importance of setting goals." When the talk was over, a parishioner informed her she had instead given a talk on "the importance of setting bread." At least she was close.

SLOWLY, imperceptibly, prog Phrases involuntarily flit through the brain. At night, between or in dreams, some Chinese words make a tentative appearance. The rhythms are seductive. By day, I wow unknowing friends with phrases as inane as they are mellifluous. "Wo de gege shi dai fu," or "My elder brother is a doctor." Never mind that I have neither a brother nor a doctor in the family.

After six weeks and 18 lessons I know the words for "comrade," "peasant," and "work unit," not to mention a variety of ways to ask for "lantern slides" and "magnetic tape." But I still can't say "I'm hungry."

And, of course, you cannot say you are learning Chinese until you tackle the characters, as the written words are called. It's easy to swoon over these delicate calligraphic strokes, the gentle word poems that have evolved into ideographs. But try writing them. My fat thumbs and leaky pens are appallingly uncooperative at rendering these subtle figures. It is as if I am trying to engrave with a blowtorch. Lines melt and run into each other, and each distinctive character is reduced to a tentacled smear.

I believe in "cultural relativism" -- a phrase I picked up at a recent orientation program -- if it means what I think it does: different strokes for different folks. But parochial or not, there's something to be said for a language with alphabetic elements that can fit into a 10- ounce can of soup with room for broth. Take the word for "I." In English, that's one simple downward stroke. If you're feeling artsy, you can draw it out to three. But not in Chinese. "I" is "Wo." To say it, imagine yourself reining in a team of spirited horses. To write "Wo," in Chinese, it takes seven strokes, the planning of the Army Corps of Engineers and the calligraphic patience of a quattrocento monk.

According to the Berlitz book I hold in my hand, there are some 50,000 characters, 5,000 in common use. It takes about 3,000 just to get through the morning paper. I will soon be tested on 200 that were at one time or another in my repertoire. Most have already slid off my Teflon-coated memory. When perturbed by it all, I recall that things can be worse: there are nine groups of dialects, six of which are not mutually intelligible.

One in four Earthlings may speak Chinese, but among American college students, it's last on their list of Top 10 hits. When it comes to enrollment, Chinese lags behind Spanish, French, German, Italian, Russian, Latin, ancient Greek, Hebrew and Japanese. (It is ahead of Portuguese.)

I'm sure somewhere out there some Chinese scholar is shaking his head and saying, "but the grammar is so simple and lean -- no tenses, no plurals, no masculines and feminines." Fine. Chinese has the grammatical simplicity of a Calder mobile swinging from an unseen thread in an unseen breeze. Simple, sure. So simple it can't be accounted for, only accepted.