During June's London Freedomfest concert celebrating the birthday, and the life's work, of imprisoned South African leader Nelson Mandela, Johnny Clegg found himself -- like millions of people around the world -- just watching.

By rights, he should have been onstage with his band. After all, for almost two decades, Clegg, 34, has immersed himself in Zulu culture, melding South African music and Western pop a good decade before Paul Simon's "Graceland." Clegg's original band, Juluka -- Zulu for "Sweat" -- was the first mixed-race band in South Africa, as well as that country's most consistently successful pop band.

Tomorrow night Clegg brings its successor, Savuka -- Zulu for "We have arisen" -- to the 9:30 club, where the supple polyrhythms and bilingual, politically charged songs will get the hearing denied at Freedomfest by the British Musicians Union's unbending enforcement of the ongoing cultural boycott of South Africa.

"I was disappointed that I couldn't perform and share the birthday of a man whose ideals of a democratic, nonracial future I share," Clegg says. "But at the end of the day it was the effect of the concert which was more important." A poll taken after the event, he notes, showed that 70 percent of the British public was more fully aware of Mandela's plight and the horrors of apartheid because of Freedomfest.

In subtle ways, Clegg has pursued a similar informational mission for years. But while he's quite successful at home in South Africa and in Europe, he remains virtually unknown in America, despite opening on various legs of the current tours of Steve Winwood, Sting and George Michael. Ironically, Juluka's first two American albums on Warner Bros. were watered down for being "too Zulu" -- just before the release of "Graceland." And while Savuka's albums have been selling well in hip urban areas like Washington, Boston, New York, Dallas and Atlanta, radio has been slower to respond to the band's bright, high-spirited Afro-pop.

"We're still battling with radio play," Clegg said last week from Toronto, where he was opening for George Michael. "The United States is a highly formatized situation, and there's nothing like it in the world as far as I can see." In South Africa, of course, programs play either English or Zulu music, never both. Except for a few superstars, there seems to be a similar barrier between black and white music on the airwaves here.

"There's a subtle variation, though," Clegg says. "In America, it's not enforced by law."

Although he's spent much of this year touring, the British-born Clegg remains committed to living and working in South Africa, where his family moved when he was 6 years old. While he retains his British citizenship, he is a permanent resident of South Africa and "a part of the broad progressive cultural movement that has been developing over the last five or six years. Unfortunately, now a lot of the best people are leaving and for there to be some kind of infrastructure -- cultural and otherwise -- for genuine social change, we've got to have those people back there, working and helping and sticking it out."

As a teen-ager in Johannesburg, it was his own neck Johnny Clegg was sticking out.

He'd gone through an awakening early, when his mother had remarried and the family moved to Zambia for two years. "At age 9 I went to a multiracial school for the first time," Clegg recalls, "and when I came back to South Africa I had a different lens on the world."

Five years later, that lens was given focus by Clegg's sudden, and apparently still unquenched, fascination with kwela and umbaqanga, the irresistible township jive practiced by Zulu migrants.

"I was crazy about street music," Clegg says, and the shimmering sound of guitarists in particular. "They had reconceptualized this Western instrument completely, seen it from a totally different angle, retuned it, picking it in a strange fashion, not playing chords in the classic sense, just picking in a running stream of notes. They were doing all this and making an incredible sound using no more than five frets -- a whole section of the guitar was left completely unused.

"It was the mystery of it all that led me to the black side of Johannesburg, which I never knew existed. It became a secret world that I used to slip into when I needed a fix ... and I needed a fix every day."

And so at 14, Clegg did something few white South Africans ever get around to: learning the language of the Zulus. "I started immediately and was speaking fluently by the time I got to university," he says, though "it was hard to pick up clicks and guttural sound, and the grammar was the language of the streets. I certainly knew more street images and metaphors than the Royal Zulu that's taught at the university. It's nearly a different language, like teaching Shakespearean English."

He'd go into the black migrant hostels, Clegg recalls, tape-recording the music, learning the songs phonetically. "I often didn't know what I was singing," he says, "and I would learn some hard-core, erotic, migrant-worker numbers and sing them very seriously, with lots of emotion, which really used to make the migrants laugh."

His excursions didn't sit well with his family, his peers or the police, who arrested him for the first time at age 15 for being in a restricted area. But "even when I was being arrested, I wasn't doing that to make a political statement," Clegg says. "I was doing it because I loved the music, the dance, the culture. The world was structured in such a way that if you wanted to get that stuff, you got into trouble. But I felt there were holes in the fence that I had to find, and I found them ..."

At first the black workers were amused -- and perhaps also suspicious -- of the white teen-ager's interest. "But that turned into positive support after two or three arrests, when I kept on coming back. The first time I was arrested at a war dance inside a hostel, the dancers said, 'Look, the police have come to fetch their white boy.' "

Which they had, to the temporary relief of Clegg's mother. "She was worried because the police were saying they'd caught me inside a very dangerous place where even they are afraid to go without guns -- 'These are wild tribal Africans fighting with each other with knives ... beer-drinking ... prostitution ... stolen goods ...' They really painted a picture -- and that was an element of the life of a migrant, but that wasn't the only element, and I was there for the music. When I came back and was arrested and kept coming back, the workers rallied around me and the next time the police came they said, 'This is our boy, he's not bad, he's working with us.' "

In performance, Clegg and drummer Dudu Zulu often break into inhlangwini, high-stepping Zulu war dances -- another cultural element he had to absorb the hard way. "Different cultures wire up the human body in different ways," Clegg notes. "I had to learn the way the Zulu male body was wired up, I had to learn stick fighting and all these other things. It was a privilege and extreme pleasure to be made privy to such a tremendous cultural secret." Clegg has been "incorporated" into three Zulu clans, though he cringes at the "White Zulu" moniker the press sometimes attaches to him.

After graduating from high school, Clegg decided that "the closest place I could get to the tribal lands was a game reserve, so I was going to become a game ranger. It was all very romantic." His mother managed to talk him into going to the university, where he struggled through to an anthropology degree (though he would subsequently teach at the college level before music beckoned full time).

"I didn't care about Western culture or being articulate in my own culture," he says. "I was still dreaming of getting out in the bush and being with people whose language and culture I was emotionally connected to."

Clegg's first important Zulu contact had been Mntonanzo Mila, a local apartment cleaner who also played street guitar, and "in my last year in school, I met Sipho Mchunu. Apparently he'd heard of a white boy playing Zulu guitar and didn't believe it. The street music tradition is very competitive and he came to where I was living and challenged me to an informal contest. And he was so good, he was playing things I'd never seen or heard before ... and he was just 17!"

Out of that competition Juluka was born. But in the early '70s, a mixed band simply couldn't play in public, "so we performed at private venues, hostels, shabeens, gambling dens, had informal competitions on the rooftops of apartments." Juluka released its first single in 1976, its first album in 1979, and started playing more publicly -- for multiracial audiences -- in 1981. Police shut down many of its shows, however -- often while they were in progress -- when they found whites playing in the townships.

By 1983, South Africa's ruling party introduced some limited (and, Clegg says, mostly cosmetic) reforms at the social and cultural level. "The government has desegregated a large percent of the commercial venues in South Africa, except in some of the more conservative, right-wing areas," he says. "There are places we don't play, either because the audience might come with baseball bats or because the halls are segregated." Still, "there are now a lot of mixed bands; it's become quite fashionable."

Meanwhile, Juluka turned into Savuka after Mchunu decided to return to his homeland to become a farmer. Drummers Dudu Zulu and Derek DeBeer continue with Clegg and three new musicians.

Savuka will participate in the African leg of the upcoming Amnesty International world tour headlined by Bruce Springsteen, Peter Gabriel, Sting, Tracy Chapman and Youssou N'Dour. The tour will offer the kind of public antiapartheid expression evident not only in Clegg's songs -- "Asimbonanga (Mandela)," about jailed dissidents, went to No. 1 in France -- but also in the band's very structure.

In South Africa, of course, such expression still must be limited, which is why many of the band's songs have been routinely banned by SABC, the state-run radio network. "It's basically through our live shows that we sell albums," Clegg says.

Over the years, however, he has "developed a way of dealing with topics that are either taboo or have been legally declared impossible to debate or discuss, like consumer boycotts or the controversy surrounding military service ... "For instance, you cannot say anything onstage which directly encourages young white males to think about the moral implications of doing military service in a white army. I may not do that under penalty of a five-year jail sentence -- but there are ways of dealing with that in terms of metaphor, oblique references and humor. It's all part and parcel of the show.

"We get as much as we can out of the legal precedents that have been set in certain court cases, and in what's happening in the space that's been provided by the cosmetic changes ... We use those spaces, we use those changes. They create important footholds for us to articulate where we're going and what we're doing."