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.