The Arab world has an unlikely new star: an American who sings — but barely speaks — Arabic. Not only that, her genre is traditional Arab music.

Plucking her oud, an Arabic version of the lute, and singing with the undulating emotion of Umm Kulthum, the Arab world’s legendary diva, the 23-year-old Jennifer Grout has become a sensation across the Middle East as a contestant on the reality show “Arabs Got Talent.”

She will appear in the finals in Beirut, Lebanon, on Saturday, competing for viewer votes against an array of Arab performers, many of whom would be at home on a Western stage: comedians, hip-hop dancers and jugglers. The only performer of classical Arab music will be an American of European stock.

Ms. Grout’s success has inspired intense discussion in the Arab world. Since her first appearance on the show, in June, she has earned fans, skeptics and critics; the invisible chorus of social media has been busy.

Her abilities are undeniable. “You don’t speak a word of Arabic, yet you sing better than some Arab singers,” said Najwa Karam, a popular Lebanese singer who was part of the panel that judged Ms. Grout’s performance. “We have for so long imitated the West, and this is the first time that a person who has no link whatsoever to the Arab world, an American girl who does not speak Arabic, sings Arabic songs.” Ms. Karam later faced a barrage of criticism for supporting an American as a finalist for the show, which ordinarily includes only Arabs.

“So many times I’ve heard the comment ‘It’s “Arabs Got Talent” — go back to America,’ ” Ms. Grout said in a recent phone interview from Marrakesh, Morocco, where she lives. “It’s like I’m starting an invasion, when really I just love singing Arabic music and desperately wanted a chance to perform it for an audience that would appreciate it.”

Her flair in doing so has also incited a wave of incredulity about her ethnicity: Ms. Grout, who is from Cambridge, Mass., describes her background as English, Scottish and Native American.

The audience’s confusion might be understandable. In the performance that sent her to the finals, she wore a flowing blue gown and was accompanied by background dancers, a laser light show and machines expelling wind and smoke.

It took courage for such a newcomer to venture into hallowed territory. In her first audition, a judge, speaking in Arabic, asked her name, but Ms. Grout indicated that she couldn’t understand the question. So the audience was stunned when she coaxed characteristically syncopated sounds from her oud as she sang along in Arabic.

The bewilderment deepened because Ms. Grout speaks English with an oddly unplaceable accent. “I always loved the fact that I had my own accent, and nobody ever could pinpoint where I was from,” she said. “But now it’s frustrating because people are using it to try to take away my credibility as an artist. “

Some Arab musicians dismiss the fuss altogether, framing Ms. Grout’s accomplishments in classical Arab music as a sign of a more thorough and reciprocal globalization. “The assumption seems to be that there is nothing special about the global South imitating Western culture, since that is just the way of the world,” said Mariam Bazeed, an Egyptian writer and vocalist in New York. “But when a Westerner deigns to imitate ‘ethnic’ cultures, then it’s suddenly this great act, worthy of documenting.”

Ms. Grout, the daughter of a pianist and a violinist, began studying music at 5. She picked up classical Arab music in 2010 as an undergraduate music major at McGill University in Montreal when she discovered an article on the web about the Lebanese singer Fairouz. “I listened to her voice online and fell in love with it,” she said. “I started to listen to other Arab musicians, and then I had an oud made for me in Syria.” Soon she was performing at a Syrian restaurant in Montreal.

Classical Arab music competes with the ascendance of Western-style pop among younger generations of Arabs. “She is focusing on a repertoire that is becoming lost among the youth of the Arab world,” said Amir ElSaffar, an Iraqi-American musician and a curator at Alwan for the Arts, a Middle Eastern cultural center in Lower Manhattan. “Umm Kulthum, Fairouz, Asmahan and others, while they are familiar since they are still ubiquitous in taxicabs, local shops and television programs, generally do not resonate with the young generation in the same way some rappers or modern pop singers do, who are talking about issues like love and politics in a way that is more pertinent to our times.”

The nuances of Arab music can be difficult for foreign ears to perceive. “Western classical music is based on the art of harmony, and the melody is restricted,” said Simon Shaheen, a Palestinian oud virtuoso and professor at Berklee School of Music in Boston. “Whereas, in Arabic music, the system is based on rich melody that depends on microtonality, or the sounds that fall between the white and black on the piano.”

Mr. Shaheen worked with Ms. Grout at an Arabic music retreat in 2011. “She can reproduce the microtones that are so important to Arab music,” he said. “The other critical element of Arab music involves ornamentation, to enrich the sound. She does this, and she reproduces the Arabic words, including the vowels, very nicely.”

Ms. Grout’s involvement with Arab culture continued after college last year, when she traveled to Marrakesh. She recruited the musicians who occupy that city’s famous Jemaa el Fna square to instruct her in Berber music, which is indigenous to Morocco and entirely distinct from Arabic music.

After two weeks there, she moved on to Paris, where she worked as a subway busker for three months. “I would step onto the train and hold out my hat and start singing Arabic music,” she said. “Some days I made decent money, other days hardly anything. But, eventually, I figured out which train lines had the most Arabs on them. Once a man on the train shouted at everyone to be quiet so that he could listen to me.”

Ms. Grout moved back to Marrakesh, where she’s been performing Berber music and learning both the Berber language and Moroccan Arabic.

Ms. Grout is measured about her success on the television show. “Arabic music is a love that will stay with me for the rest of my life,” she said. “But it doesn’t end with a talent show. It’s a challenge that takes a whole life to master.”