For Kariamu Welsh and the members of Kariamu & Company, Friday-night rehearsals are serious business.

"Let's take it from the last one into the push-off, OK?" says Kemal Nance, Welsh's assistant, who began studying with her 31 years ago when he was 8. He puts the core group of five women through their paces while she observes.

Except for Saleana Pettaway, a 15-year company veteran, Welsh and Nance are working with a newer crop of dancers on Anthem, a piece about homelessness originally choreographed in 2002. Welsh, who turned 60 last month, encourages the dancers as she corrects them, saying, "Ladies, I'm working backwards, but you hold onto that and remember it!"

They are preparing for performances this Friday and Saturday, the first major events of the 40th-anniversary celebration of Umfundalai, an African-Caribbean-diasporan dance technique that was created by Welsh in 1970 and that continues to expand as it absorbs new influxes of information. Anniversary events will stretch into next spring.

Umfundalai means "essence" or "essential" in Kiswahili. Welsh explains: "The technique is predicated on the premise that there are common aesthetic elements in African dances, regardless of the region of the world that the movement comes from."

Many modern dance techniques carry the names of their creators - Graham, Cunningham, Limón. Welsh wanted instead to create an umbrella to shelter a movement community that would be inclusive, not exclusive. "It's a very open-ended technique, unlike what we may normally associate with technique - that's why it's not named after me," she says.

Remarkably, the concept driving this technique is closer to ballet than to modern dance and parallels the way ballet has evolved. All ballet choreographers - from Petipa to Balanchine to the Pennsylvania Ballet's own Matthew Neenan - make dances using what audiences can recognize as a ballet vocabulary while infusing it with their own new movements, some picked up from other sources. The same thing happens with Umfundalai, except the content is African, rather than ballet.

Welsh, whose doctorate is from New York University, received a master's in choreography from SUNY Buffalo in 1975 and studied with the great Pearl Primus, who told her to pursue the history of African dance and go beyond her "very romantic notion of Africa."

Within a few years, she was living, teaching and performing in Zimbabwe, where, soon after the country's independence from Britain, she became the founding artistic director of the National Dance Company of Zimbabwe (1981-83).

Welsh, a widely published scholar of African dance, currently heads the dance department at Temple's Boyer College of Music and Dance and is artistic director and principal choreographer of her own Kariamu & Company.

"I've never been what one would call a traditionalist," she says. "I want to express myself in a contemporary fashion, using vocabulary from the African diaspora."

She builds on ageless movements in dances from, say, Nigeria, Jamaica, Guinea, or Guyana to create modern versions that will meet and mesh with her choreographic vision.

She gives as an example "what I call the Nigerian Stomp, in northern Nigeria - and stomps of different kinds are prevalent throughout Africa" - which she transformed by stylizing it and moving it from its indigenous context to a concert dance environment.

In other words, her dance language grows in the same way that one spoken language borrows words from another, altering them through the process of translation. Dancers she encounters on her travels to diasporan lands may show her movements that she will, again, stylize and incorporate into the Umfundalai vocabulary. Nance is her living database; with the choreography stored in his brain, when Welsh draws a blank he can recall for her the shape and pathway of a movement.

Later, she exhorts the dancers "to think about individuating your movement, now that you have the basic structure," wanting them to exhibit their singular personalities, even when they're doing unison movement.

In Anthem, to be performed this week, she ingeniously used the angular movements and torso articulations of African dance and applied them to the issue of the homelessness that is a contemporary urban problem worldwide. Also on the program is a dance Welsh made in 2000 titled The Herero Women, dealing with the African women who adopted the traditional 19th-century costumes of the German colonialists who conquered their homelands. This way of dress has become a national custom.

"I'm fascinated with that," she says. "When you first see it, you think it doesn't look right but, once you probe, you come to understand that this has become their tradition! You see that in more places than you realize," she continues, "and we know, as African Americans, we have taken on certain things, and they become ours. In this piece I use not only live accompaniment, but we also sing and chant."

Anniversaries are like retrospectives. They inspire backward glances and assessments of one's achievements. In this spirit, Welsh says, "I've studied a great deal about Africa, I've traveled extensively, but it was in Philadelphia that my maturity really ripened. Here I began to explore in ways that I hadn't envisioned before.

"I'm honored to have lived long enough to see the beauty of Umfundalai, but I also recognize that I'm just one voice, one expression."

If You Go

Kariamu & Company: Traditions

7:30 p.m. Friday, 2:30 and 7:30 p.m. Saturday, Conwell Dance Theater, Broad and Montgomery Streets, Temple University. Tickets: $15-$20. Contact 1-800-298-4200 or www.liacourascenter.com/upcoming-events/box-office (click on Buy Tickets, then Temple Dance).