If you grew up on American jazz singers, Lena Willemark will throw you off at first. She doesn't swing in the usual sense and she's not working from the Great American Songbook. Her voice comes out of kulning, the old Swedish technique herders used to call cattle across valleys, all open throat and piercing high notes, and she grafts that onto songs sung in the Älvdalen dialect of her native Dalarna, a language so old and isolated that linguists sometimes classify it as separate from standard Swedish.

What makes her worth knowing for jazz listeners is who she chose to play with. She's spent decades in dialogue with improvisers, most notably the multi-instrumentalist Ale Möller, with whom she made records that treat Swedish folk material the way a jazz quartet treats a standard: as a starting point, not a museum piece. Later she worked with the pianist Jan Lundgren, putting her fiddle and voice against his trio in a way that let folk melody breathe inside jazz harmony without either side swallowing the other.