The a cappella voices of Ladysmith Black Mambazo first reached most American ears on Paul Simon’s seminal Graceland, but the band was 25 years old by the time Simon made them the hottest world music act on the globe. Over 30 years later, they’re still recording — and winning Grammys — at a tireless pace. Founder Joseph Shabalala retired in 2014, handing the torch to his four sons, each of whom joined the group in 1993.

Founding member and tenor singer Albert Mazibuko, 70, is now the group’s elder, shepherding the all-vocal band as they hold true to the Zulu isicathamiya tradition (a men’s harmonizing style that originated in the mines of South Africa) that defines their sound.

“Ladysmith Black Mambazo will be here forever, as long as the people who are in it follow the example to work hard, be disciplined, believe in yourself, and don’t be distracted,” says Mazibuko over Skype from South Africa, before the band set out for a two-month U.S. tour that begins at the Charleston Music Hall. The group tours about seven months of the year, but still performs weekly at churches and corporate functions when they’re home in Durban. They’ve also launched the Ladysmith Black Mambazo Mobile Academy, an education initiative that encourages South African children to learn and perform their traditional music styles.

“It’s been very successful. The talent is amazing,” says Mazibuko. “The idea is to introduce them to other kinds of music: how to sing beautifully, how to harmonize your voices, and how to do it right and take it to the next level.”

It makes sense that young South Africans might idolize Ladysmith Black Mambazo — after Graceland, the band collaborated with or worked on projects with Dolly Parton, Stevie Wonder, Michael Jackson, Emmylou Harris, George Clinton, and even ’90s girl group B*Witched. They’re still in high demand, and Mazibuko says they’re careful when choosing a project.

“We have a lot of requests. There are so many groups that want to collaborate with us. Our management has to look at that person and know that it’s not going to lower the standards of Ladysmith Black Mambazo,” says Mazibuko. “That’s very important. I remember Paul Simon said the other day, ‘If you are helping somebody, be careful that the person you are pulling up is not pulling you down.'”

Many of the relationships formed through musical collaboration decades ago still persist — last year, the group spent two weeks in residency at Dollywood, performing on their own and with Parton, and riding rollercoasters on their off days.

The touring lifestyle provides Mazibuko — who grew up during the apartheid era — a unique perspective on the state of race relations in the U.S. and the world.

“What is happening now, it’s always overwhelming,” he says, citing modern South Africa as an example of how distrust or hate can be superseded by coexistence. “Everyone has an equal opportunity and equal rights today in South Africa. If we can continue like this, we will be an example for the world. As our late leader Nelson Mandela said, ‘We are a rainbow nation.’ You can see the rainbow nation everywhere in South Africa.”

During and since the apartheid years, Ladysmith Black Mambazo have served as ambassadors for their nation, demonstrating the value and beauty of African cultures after centuries of oppression. Their contributions don’t go unrecognized — their website includes a section dedicated just to “Grammy Award News,” because every recording seems to garner nominations. Last year, they won the award for Best World Music Album for their rerecording of Shaka Zulu, a landmark originally produced by Simon. What’s most impressive about the award is its recording after Joseph Shabalala’s retirement.

The group’s next album, currently in mastering and scheduled for a 2019 release, is comprised entirely of new, original songs by Shabalala’s sons.

“It will be a celebration,” says Mazibuko, who celebrates 50 years with the band this year and hopes to perform for 20 more. “The new songs will have a good impact on people. They have a positive message, and I hope Ladysmith Black Mambazo will continue to be blessed.”