The three Roche sisters sit down for a noon breakfast and agree to a format as rigid as any presidential debate: No interruptions, and whoever is speaking gets to complete a thought by herself before rebuttal or explanation. Past talks with the outspoken and loquacious singers have been known to degenerate into verbal anarchy.

Even normally unflappable talk-show host Tom Snyder had some trouble handlng their fractured counterpoint when the Roches visited his "Tomorrow" show recently. Afterward, a viewer "sent me a check for $6," laughs Terre Roche. "It was for a hit of whatever we were on."

Roche insouciance extends to their music, which they brought to the Bayou last night -- a blend of folk tradition and lacerating lyric fancies laced with elements of jazz and classical structures, Andrews Sisters pop vocalese and modern dance/kung fu motion. "We're an antidote in the music industry in terms of what's being offered," says Terre. "We're going against the grain. What we're talking about are things that are not necessarily soothing in a culture where everybody wants to be sedated."

The songs deal with extended families, lovers and waitresses, "nurds" (the title of their new album) and high-school misfits, commuter trains and other sundry slices of real life. Their contemporary folk cabaret bustles with Jules Feiffer-like characters whose tales are told in hypnotic harmonies that seduce even as they alarm. If they make a film about these women, they would name it "Middle-Class Crazy."

Coming out of an Irish, middle-class suburban background (their father developed the language-skills tape course called Speechmaster), the Roches structure their songs with an arch intelligence that is, oddly enough, also a mark of the lyric side of the best New Wave. "People's music is a composite of their own environment, personality and the times they live in," says Terre Roche. "You're always drawing on your own resources. But people have an urge to isolate somebody as a genius. Everybody's looking for a hero."

Our heroines. Which may partly explaine why the Roches became the darlings of the critics in 1979, when their debut album was released. The Roches are different: three woman playing their own folk-angled contemporary music, backing themselves with acoustic guitars and some of the most magical natural harmonies in the business. Yet the lyrics demand attention, whether the silliness of their signature song, "We" ("We are Maggie and Terre and Suzzy/We don't give out our phone numbers/Sometimes our voices give out/But not our ages and our phone numbers") or the cold conclusions of "The Married Men" ("Makes me feel like a girl again/To run with the married men").

Though they are sisters by blood, the Roches are as different as the components of a fruit salad. Maggie, 28, reflects her on-stage persona: austere, serious, passively quizzical, she spends a lot of time with her head bowed, thinking, assimilating. Terre, 26, seems the most level-headed, answering questions surely, confidently. Twenty-three-year-old Suzzy (rhymes with fuzzy) is all hands, cutting the air and pushing words out of the way for a rush of more words.

The Roches expected to join the Smothers Brothers on the night of Nov. 1, when the brothers returned to network television. Instead, the sisters were playing a concert. Although they had been asked to rehearse all week for the show, they were dropped from the final taping -- and the Roche Sisters are still angry. They believe that their image contributed to the problem. "We're not trained in the Farrah Fawcett school of being female. I'm not angry or anything," says Maggie, without meaning it.

The sisters point to an "energy difference" between Hollywood and New York, to which they gravitated after being raised in Park Ridge, N.J. After learning to play guitar from public television, Maggie and Terre had a misdirected fling at a music career in 1975 with a Paul Simon-propelled album project (they had attended his NYU songwriting seminars). The ablum was an artistic compromise as well as a commerical failure. After burning up tapes and lyric sheets, the two sisters moved to Hammond, La., living in a kung-fu temple while waiting tables at a restaurant.

It wasn't until Suzzy joined the ranks in 1976 that things jelled. They returned to New York at Christmas -- performing in the streets and on subways as the Caroling Caroliers. They must have presented an awesome sight; their clothes have always looked like Goodwill rejects, and their choice of shoes seemed based on the "if it fits" premise. Still, clubs started letting them appear on their stages and when their debut album came out, critics reached into the farthest corners of their thesauri for animated adjectives.

The group moved from opening act to headline status in major clubs and small concert halls by constructing sets that run from bleak ballads to madrigal romps to jazz journeys and classic pop pablum done in inimitable Roche fashion. In 1967, long before NYC, Maggie fumed at Terre when she ran off to New York with her best friend for a Paul Simon concert. Last month, Terre got a little bit of revenge when Simon asked her to join him for a duet in his New York concert at the Palladium. "It was one of the best nights of my life," she beams.

Still, it's their own work that excites the sisters. Their records still don't get a lot of air play. "We don't allow our music to be played on the radio," says Terre, joking, "we get a court injunction if we hear it's being played on the radio."

Seriously, she adds, "as long as we're the only people who understand what we're doing, I feel like John Anderson. We're running on an independent ticket."