‘When I was growing up, I couldn’t listen to any bands or artists in my language,” says Katarina Barruk. She is one of only a handful of remaining speakers – and the only one of whom is an internationally celebrated singer – of Ume Sámi, one of the nine living Sámi languages that today is on Unesco’s critically endangered list. It’s spoken by a handful of Sámi communities living across the part of Sápmi (the territory of the Sámi peoples across northern Scandinavia) that’s now in north-east Sweden. “We have been working so hard to get to the point where you can hear the language at the Royal Albert Hall,” says Barruk. “It’s amazing.”

And not only to hear the language, but experience it sung by Barruk in her own music, recomposed and remade with the Norwegian Chamber Orchestra. They’ll be led by the violinist and conductor Pekka Kuusisto, in a Prom that will take the audience on a journey “into my universe”, she says, “so that people can understand that this language is alive”. The Prom is a symbol of hope and defiance for Ume Sámi and its speakers, and for the Indigenous peoples of Sápmi as a whole, she tells me. “I want to give something hopeful to my own people.”

It’s also a big moment in her own life. “The whole of my family is coming. My brother, even. He’s a reindeer herder and he never has time for travelling, but the end of August is the only time of year he can leave. It’s really huge to hear the Ume Sámi language in one of the world’s biggest concert halls.”

But for Barruk, the significance of the Prom isn’t only about representing her language: it’s about creating a new chapter of cultural survival for her people. Her songs, all in Ume Sámi, are based on joiking traditions, the traditional vocal art of the Sámis, and mix the joik’s skirls of high-register cries with melodies of depth and soulfulness.

Her second album, Ruhttuo, released in 2022, was a fusion of a contemporary soundworld with timeless traditions. That’s the basis of the Proms collaboration, too: “I’m not only doing traditional joik in the concerts. My vocal practice is really affected by my personal exploration of how I can play my instrument – my voice. When I was growing up, all the vocal sounds I made were always supposed to mean something: a place, a person, a mountain, an expressive state. So I was always emotionally exhausted after the concerts. But now I can sometimes make sounds for the sake of making interesting sounds, and then it becomes even more fun.”

But at the Proms, she will be singing songs “about dreams, about time, about being in the present tense. And there is one traditional joik, Miärralándda (Coastal Lands). There is also a piece about my great-grandmother, whose sister was one of the people who took the initiative to have the first Sámi gathering. I have strong foremothers in my family who have always been fighting for Sámi rights.”

Barruk’s music is a parable of Sámi culture’s place in the world now. “My music is always affected by western music. You are always part of that society. The question is how much do you assimilate to fit in, as an Indigenous person? How much can you work to help each other and use the new ways that are available to lift up our voices?”

That means recognising the fragility and threats to Sámi people, and to Ume Sámi speakers in particular. Neither Finland nor Sweden has ratified the Indigenous and Tribal Peoples Convention of 1989. Norway has, but Barruk says that it has continued to violate the rights of Sámi people. And across Sápmi, she says, “they are getting rid of the Indigenous people” to make way for mining in the boreal forest. Reindeer herders and Sámi people have had to move to make way for mining, and the environmental desecration that brings – and for wind farms, too. “When you are ‘green transitioning’, you are often getting rid of the Indigenous people,” she says.

These are issues of survival and self-determination that are burned into the inspiration behind Katarina’s compositions and performance. “When I started making music, I always thought about my community, my people, my culture. I love them so highly and I know what kind of dark times we are living in, and how we are fighting on a daily basis.”

So what can the musicians of the Norwegian Chamber Orchestra, who first collaborated with Barruk in Oslo in 2023, add to her searing music? “It’s amazing to hear the music you’ve written played by so many human beings, and how that changes the dynamic,” she says. The piece that comes after the song about her great-grandmother, Barruk says, “feels like it’s playing in her honour”. That music, Kuusisto tells me, is Max Reger’s version of Bach’s chorale setting O Mensch, Bewein Dein Sünde Groß, music that’s an exorcism of humanity’s sin and pain.

Barruk, her band and Kuusisto share the stage with the orchestra in the first half of the concert, alternating her songs with classical and contemporary pieces from Caroline Shaw to Michael Tippett to Philip Glass, which Kuusisto has chosen for their tradition-transcending resonances. He says his choice of music is an exploration of how “composers respectfully re-read ancient knowledge and earlier traditions”: the way that Tippett reimagines Purcell in Sellinger’s Round, and how Shaw puts Ravel and Mozart in suspended musical animation in Plan and Elevation, analogies of how Barruk rethinks the ancient traditions of Sámi music. “Every generation has to reinterpret concepts that previous generations have taken for granted,” he says, “including things such as religion and nationalism, which play a big part in the treatment of Indigenous people worldwide – plus, are more often than not the driving forces behind war.”

There are stories of oppression in Kuusisto’s setlist, too. Kuusisto will play Hannah Kendall’s Weroon Weroon, written for him in 2022, in which “you basically put the violin under arrest”, he says. In her programme note for the piece, Kendall explains that “the strings of the violin are bound together with three aluminium dreadlock cuffs; afro hair accessories that distort the sound so that pitch production becomes unstable and unpredictable. A new creolised instrument is formed as a result.” The violin is denatured, forced into sonic contortions: a musical mirror of colonial oppression.

The second half, for the orchestra alone, ends with the darkness of Shostakovich’s eighth quartet, a scream of the individual against Soviet tyranny.

Kuusisto says that working with Barruk has changed him and the orchestra. It’s all too easy for the culture of orchestral playing to become complacent, a job rather than a vocation, he says. But “when Katarina sings, it’s an act of preserving a culture. It’s an incredible thing to witness music-making in which the motivation is so radically different from what we’re used to. In fact, I would venture that we are not even so used to thinking about what the motivation is in our work in classical music at all. Which is why Katarina is vitally important for us, to make us think about what we are doing, and why we are doing it. It’s one of those experiences where we collectively feel we are standing on more solid ground.”

For Barruk, “it’s huge and impactful and powerful that the Ume Sámi language has survived against all odds”, she says. “It’s alive even when it is not supposed to be, if the programmes to eradicate it had worked in earlier centuries. And that brings another level to my music, because I am able to sing in an Indigenous language. There is such a resilience within our people.”

For one night this summer, Barruk and Kuusisto’s Prom will turn the Royal Albert Hall into an outpost of Ume Sámi and the people of Sápmi: their traditions, their hopes, and their defiant and urgent cultural future.

• Katarina Barruk, Pekka Kuusisto and the Norwegian Chamber Orchestra are at the Proms on 31 August and live on Radio 3, and then on BBC Sounds until 12 October.