A dialogue across the luncheon buffet table:

Alvin Chow: "Al, what do we disagree on?"

Alan Chow: "I don't know. Do we?" (A moment of thought.) "Oh, I'm not well-organized."

Alvin: "I am."

Alan: "So I think he's over-organized."

Alan and alvin Chow are 22-year-old, Chinese-American, prize-winning pianists-and twins-who yesterday graduated summa cum laude in music from the University of Maryland and jointly gave the student commencement speech-speaking in alternating paragraphs.

"We didn't want to do alternating sentences-that would be silly," said Alan.

"And we didn't want to give separate speeched."

They are the same height, have identical layered haircuts, and wear silver-framed glasses. They also were accidentally dressed alike in dark blue suits, white shirts, black shoes, and blue print ties (with different prints at least).

"We had planned to wear different suits," said Alvin with a chuckle, "but he forgot his other suit at home. So here we are dressed alike."

They are a study in tandem and they've come to like it that way. They play push and pull with their music, critiquing the other's work, going their separate ways during the day, only to meet over their ritual dinners every night to catch up on what's happened.

They graduated with straight-A averages-among the tops in their class. "That's what they tell us," they said jointly, in an interview, then laughed.

"Sorry," said Alvin, gesturing for Alan to go on.

The Chows were invited to apply for the commencement speech.

"I think they thought we were highly unusual," said Alan with a grin.

"Extremely strange," added Alvin. "Both music majors, both with the same average, Chinese . . ."

For the speech, Nancie Gonzalez, U.M. vice chancellor for academic affairs, recruits top-ranking students, with different majors from last year's speakers, who seem to be able to handle public speaking. "I interviewed them together," said Gonzalez. "Why not? There was no way on paper to choose between them."

Alvin said that during the interview, "We said we felt more comfortable piano-playing than speaking." So the university let them do both. The two gave a standard graduation speech, then treated the crowd to their music, too. Alan played first-"Prelude in B Flat Major" by Rachmaninoff. Alvin played "Scherzo in B Minor" by Chopin.

Both will attend Juilliard School of Music for graduate work, and both have been piano soloists with the Miami Beach Symphony. They've also both appeared as soloists with the National Symphony Orchestra after winning competitions and both have been honor recitalists at the Mozartium Sommer Akademie in Salzburg, Austria.

Alan recently was declared the national winner in the Music Teacher's National Association Collegiate Artists Competition.

"We try to avoid doing the same repertoire," said Alvin. "We have different ideas about music."

"And if I'm thinking about doing a piece that Alvin's been doing for the past two years," said Alan, "it won't be my first choice because I've just heard it so much."

While in school, they generally squeezed five hours of music between classes. Each had an all-night pass to the music practice rooms at Tawes Hall.

At home in Miami, where they return for summers and vacation breaks, they divide up practice time on their parents' Steinway grand. There also are two upright pianos in the house, but a Steinway is a Steinway. "If one of us has a big recital coming up, that person gets priority time on the Steinway," said Alan.

They enter the same music competitions all the time. "It's never bothered us," said Alvin, "if the other won. In only one competition did we tie. We're individuals. We're different pianists, and we sound different. One judge may like the other over another."

There is one advantage to the double-teaming: "Higher visibility," said Alan. "In competitions, they remember there are two of you."

At Maryland, they inevitably both got invited to the same parties. ("Well, we do spend most of our time in the music department," said Alan, "so that's where most of our friends are.") On campus they smiled and said hello to whomever, because oftern the person was a friend of the other twin. "You don't want to be rude to anyone." And, they date. "But not the same girl," said Alvin laughing.

It was not always this way. "When we were in elementary school, they made a special point of never having us in the same class," said Alvin.

They started taking piano lessons at age 5. "I thought music would help them study," said their Canton-born mother, Shirley Chow, an attractive woman immaculately dressed in a white suit and blouse, who with her husband, Louis Chow, came north for the graduation. "I had a theory that music would help them memorize things and that would help with their schools work," she said.

"We came to enjoy performing," said Alvin. "Unlike our brother. He just didn't enjoy performing." Their brother is Dennis, seven years older than the twins, who early on gave up piano lessons.

"We're close to him, but we were in sixth grade when he went to college," said Alvin. "So we were only children for a long time."

Then there is the question of their constant use of "we."

"Ah, you noticed that," said Alvin laughing.

"It's very hard not to do that," said Alan. "We have made an effort-well, there's 'we' again . . . we have been there's on changing it. The more we use it, though, the more people think it's cute, a novelty. We are individuals, but we never want to lose that sense of togetherness." CAPTION: Picture 1, Alan and Alvin Chow; Picture 2, Alvin at piano, by Margaret Thomas.