Some songs and music affect us more than others. It could be what the lyrics are saying, the way the melody turns or just a certain chord sequence. Or the reason may run deeper.

Some songs and music affect us more than others. It could be what the lyrics are saying, the way the melody turns or just a certain chord sequence. Or the reason may run deeper.

When Mor Karbasi first sang Ladino songs as a teenager, she couldn't understand why she was so touched by them. The daughter of an Iranian father and a mother of Moroccan descent, she was born in Jerusalem and feels Jewish. But she always felt drawn to Spanish culture. Ladino is the language of the Sephardic Jews who were expelled from Spain in 1492 and made new homes in the Balkans, the Middle East and north Africa.

Karbasi told her grandfather of feelings these songs aroused and he wasn't surprised. The phrase he used is "the blood never forgets", and he went on to explain the reason the women on her mother's side of the family looked Spanish was simple: the family had been part of the Sephardic diaspora. These Ladino songs were her heritage.

There's a striking parallel between Karbasi, who was one of the stars of Celtic Connections 2009 and makes a swift return to Scotland this weekend, and Diana Jones, the American singer-songwriter whose work reeks of Appalachia. Jones was adopted, grew up in New York and only later discovered that the reason she liked country music had something to do with her birth family being from Tennessee and her grandfather being a musician.

Jones was only a generation removed, however. Karbasi's "blood memory" goes back centuries, though she empathises with Jones, whose city friends mocked her liking for "hick music" when they were grooving to the charts.

"I couldn't have discussed my feeling for Ladino music with my friends," says Karbasi. "They would have thought I was weird, too. But, then, I didn't like pop music either. I was always looking for something alternative, world music mostly, and I loved flamenco, which is the Spanish connection at work again."

Karbasi grew up singing. Her mother, a writer and poet who contributes lyrics to some of the songs in Karbasi's repertoire, used to sing to her in the house and claims the young Mor could carry a tune from the age of one. Karbasi put this down to maternal pride until her sister, who at three is 19 years her junior, started humming songs back at their mother when she was one also. "So maybe I did start early," she says. "I certainly remember driving my family crazy any time we were going anywhere in the car. I just sang all the time."

She took piano lessons from the age of five and at 14 was invited to join Meorav Yerushalm, a representative group of young Jerusalem talents. It was here she made the Ladino connection and discovered, with encouragement from one of the teachers, that she could write songs. "There was a competition coming up and they said, Why don't you write something?' And I thought, no, but I sat down at the piano and a melody came. Then I wrote some words and suddenly I realised I could do it," she says.

Looking to expand her horizons, at 18 she went to study Moroccan liturgical music with an oud player in Jerusalem. She learned Arabic scales, discovered how to improvise and, with a growing repertoire of Hebrew, flamenco and Ladino songs, decided to become a professional singer. The Israeli government, however, had other plans: national service, which is compulsory. "If you prove you have a talent, like singing, and you pass a whole series of auditions, you can serve your time entertaining the other troops," she says. "I did a month of exercises and there was rifle training that we had to do but, other than that, I spent most of my time in the army singing on military bases."

This isn't quite the soft option it might seem, since many of Karbasi's gigs were in bases in Gaza and she has a few frightening experiences that she politely declines to talk about further. There were two other reasons why she was glad to be free of the army, though: the music she was singing wasn't what she had in mind and, just before starting her national service, she had met Joe Taylor, the London-based guitarist who is now her songwriting and life partner and who plays in her band. There were, she says, many long-distance phone calls before she got out of uniform and was able to join Taylor in London and get on with her career. With one album already released, The Beauty and the Sea, which featured Indian percussion master Trilok Gurtu, among other notables, and another in production, Karbasi is beginning to make the kind of waves that have brought her heroes, Portuguese fado singer Mariza and the fabulous flamenco singer from Majorca, Concha Buika, to international prominence.

She continues to champion Ladino songs because, she says, they express her sense of identity best, and features flamenco and Hebrew songs in her concerts, too. She is also, with partner Joe and her mother, writing songs that complement the traditional material very naturally. "The thing about Ladino songs, and this is probably true about traditional songs everywhere, is that there are songs to accompany you through all the stages of your life," she says. "They may be very old songs but they're still relevant today because the things that happen in them are still happening. At the same time, though, I want to find new things to sing. Sometimes words - it might be an old text or one of my mother's poems - just speak to me and that feeling triggers a melody. Or, sometimes, something happens and I just have to write about it. Ultimately, though, it's about finding something that moves me and then trying to give that feeling to an audience."

• Mor Karbasi plays the Voodoo Rooms, Edinburgh, tonight; the Loft, East Grange, Kinloss, tomorrow; the Lemon Tree, Aberdeen, on Sunday; Perth Theatre on Monday; and the Tolbooth, Stirling, on Friday, March 13.