She doesn't look like a Spanish dancer, in her sensible pantsuit. She doesn't sound like one either -- the accent is unmistakably British. But when she moves, demonstrating a step for her students, Marina Keet is transformed: The proud, erect spine, dramatic footwork and fluid, seductive hands reveal her mastery of the art of Spanish dance.

Keet has been a professional dancer, teacher and choreographer for more than 30 years, first in her native South Africa, then in Sweden, Italy, England, and now the United States. Her accomplishments will be showcased tomorrow evening at 8 o'clock in "Fiesta Espan ola," a dance concert arranged and directed by Keet at George Washington University's Marvin Theatre.

Trained as a classical ballet dancer, Keet spent five years performing with the University of Cape Town Ballet Company and several more as a ballet teacher before deciding to specialize in Spanish dance. "Ballet is still my first love, to watch," she says. But once she began exploring the range of Spanish dance, Keet was hooked. Now her teaching, and her concerts, emphasize this variety -- not only the well-known heel stamps and castanet work of flamenco, but also the lyrical, balletic steps of "classical" Spanish dance and the vivacious, brightly costumed folk dances that Keet has traveled all over Spain to collect. Tomorrow's performance also will feature one of Keet's own recent compositions, "Bolero," choreographed to an all-percussion score by Richard Trythall, an American composer whom Keet met in Rome.

Keet's enthusiasm is infectious. In the 2 1/2 years since she moved to this city, she has established herself as a significant force in the Washington dance community, teaching Spanish dance classes at GWU and mounting large-scale annual recitals. The performers she directs are an eclectic lot -- professional, semiprofessional and part-time dancers, including university students, several teachers, a caterer, the inevitable lawyers and two interpreters for the deaf. Most have strong backgrounds in ballet, jazz or modern dance, and several know other ethnic forms, ranging from Israeli folk dance to East Indian Bharata Natyam to "belly" dancing. All have become addicted to Spanish dance, planning their home and work schedules around rehearsals and performances -- all, of course, for free.

Keet somehow manages to put on lavish productions -- including regular appearances by guest artists, some from abroad -- with no regular source of funds. "In South Africa," she says, "I worked with a big, professional ballet company. We had 60 dancers, and all my productions were financed by the government." In Washington, however, Keet has no permanent company, a fact that makes it difficult for her to apply for grant money. Despite support from the GWU dance department and the local Spanish community, Keet herself must take care of many aspects of the productions, from costumes to posters, and she depends heavily on volunteers.

The success of Keet's work also depends on her family. She has been married for 25 years to Mikael Grut, a Danish forestry economist with the World Bank, and they have three children. She says her spouse has always been "very supportive of my career. He realizes that I'm more interesting when I'm doing something, and if I burn the potatoes, it's not a major crisis." Her children have also been sympathetic, urging her to continue her work at those times when she was ready to give up.

And Keet has had plenty of reasons for wanting to give up. "Every show is always riddled with crises," she says. "Every year I say 'never again.' " So far this year, crises have been limited to one guitarist's broken arm and two major cast changes with less than two weeks' notice. "I don't even do double-takes anymore," Keet says. "I almost expect it. You have to be very, very strong, and move on, and solve the problems. Just be persistent, and plod along, and everything comes right in the end."

A choreographer whose first work was performed when she was 18, Keet maintains that she has never missed performing. Her eyes twinkle as she explains, "I always knew I wanted to tell people what to do . . . to create my own ballets, instead of just doing what I was told . . . My husband says I am 'a born teacher.' I love taking people, training them, and making it work. It's very satisfying."

Keet is also a writer. "I've had the urge to write since I was very small," she says. She has published books on Spanish dance and the history of ballet in South Africa. ("It took me 19 years, because there was literally no information available. I was teaching ballet history, and my students were learning about every country except their own!") In addition, Keet is a founding member of the Spanish Dance Society, a group established in 1965 to develop and promote a standardized system for teaching Spanish dance outside Spain.

Despite occasional difficulties, Keet says she is glad she does not have her own permanent company. "I admire those who do, but it's too complex and too expensive, and you have to be away on tour too long." Moreover, she points out, since she does not perform, her dancers are not obliged to play a subservient role. "I like the dancers I have here in Washington. It's an interesting group, full of personality . . . Nobody's competing with me, so I don't have to squash the individual dancers' personalities -- I can encourage them."