The women in Kitka are fearless explorers; you can hear their intrepid spirit in every haunting song. With a repertoire encompassing more than a dozen languages, including Ukrainian, Latgalian (spoken in Latvia), Georgian, Bulgarian, Greek and Hungarian, the extraordinary vocal ensemble often gathers material through firsthand investigation, searching out elderly women in small villages where traditional songs and vocal practices are still remembered.

"It's really important that we approach each piece with a lot of intensity and respect for what it is and where it came from, but also to transmute it and make it our own," says Shira Cion, Kitka's artistic director. "None of us are Latgalian or Romanian, but as musicians we really try to bring our whole selves to each piece."

The Bay Area-based a cappella group returns to Santa Cruz on Saturday for a concert at Kuumbwa that's part of a series of Northern California performances with Seattle's Balkan Cabaret, an acclaimed quintet featuring vocalist Mary Sherhart and special guest John Morovich, a Croatian-American singer and multi-instrumentalist. Together, the two ensembles are exploring sevdah love songs from Bosnia and Herzegovina, richly harmonized Croatian folk songs and nostalgia-laden starogradski tunes from Bulgaria, among many other styles.

Kitka's willingness to experiment and elaborate on traditional themes is part of what makes it such a singular ensemble. The group's ethic is anything but preservationist. Rather, the women communicate their love and respect for the material by interpreting it with their own distinctive sensibility as contemporary Americans.

It's an aesthetic that grew out of the group's earliest origins in 1979 as an offshoot of the Westwind International Folk Ensemble. Under the direction of Bon Singer, the group evolved from an amateur collection of enthusiasts into a finely honed professional ensemble with an international reputation.

The ravishing textures of the women's voices, the haunting cadences and unfamiliar languages make Kitka's performances an enthralling experience. It's no wonder that film composers have relied upon the group's evocative sound to heighten the emotion in movies such as Jacob's Ladder and Braveheart.

Kitka is just as effective in theatrical settings, for instance playing the Greek Chorus and Trojan Slave Women in the American Conservatory Theater's award-winning 1995 and 1998 productions of Hecuba. Highly respected in folk music circles, Kitka became the first nonnative group to perform at the National Festival of Bulgarian Folklore in 1991.

Last year, the group released its most ambitious project yet, The Rusalka Cycle: Songs Between the Worlds, a CD of Ukrainian songs traditionally sung to assuage Rusalki, the spirits of women who have died untimely or unjust deaths. Working with the brilliant Ukrainian-born vocalist and composer Mariana Sadovska, Kitka collected the songs in the shadow of the irradiated city of Chernobyl.

KITKA performs Saturday, April 26, at 8pm at Kuumbwa, 320-2 Cedar St., Santa Cruz. Tickets are $21 adv/$25 door; more info at www.brownpapertickets.com or 510.444.0323.

Send a letter to the editor about this story.