The story of how Mr. Ayup traded the freedoms of life in America for the quixotic dream of opening Uighur-language schools in Xinjiang is a cautionary tale about the perils of challenging the Chinese state on matters of ethnic identity.

At a time when the authorities are determined to tamp down even the faintest expression of Uighur self-determination, few hold much hope that he will be freed anytime soon. “The government can make sure he rots in jail for years,” said Mamatjan Juma, a childhood friend who now lives in suburban Virginia. “They don’t want a brave, influential intellectual like him on the streets.”

Despite the evident risks, friends say Mr. Ayup thought he might succeed by steering clear of politics and carefully following the regulations that govern the establishment of private schools. Soon after returning from the United States, he opened a kindergarten in the Silk Road city of Kashgar. Having quickly achieved full enrollment, he set his sights on Urumqi, where Mandarin-language public schools are producing a generation with limited Uighur proficiency.

Anwar Mamat, 38, a childhood friend who teaches at the University of Nebraska, said Mr. Ayup turned down a three-year scholarship at the University of Kansas to pursue his dream. “A lot of parents are willing to send their kids to a Uighur school, but none are available,” he said. “Abduweli knew the risks, but he was committed to achieving his goals.”

It was not long before Mr. Ayup had become a local celebrity. He appeared on state-run television to offer advice about studying abroad, and his blog posts on Uighur language drew hundreds of thousands of hits. Robert Wilson, an English teacher in New York who was a former student of Mr. Ayup’s, said he was far from a radical. “It wasn’t that he thought Uighurs shouldn’t learn Chinese, it’s just that he thought they should also know their own language,” Mr. Wilson said.

But Mr. Ayup soon met official resistance. Last year the authorities forced the cancellation of an event he had organized to mark Nowruz, an ancient pre-Islamic celebration of spring, and in March of 2013, they shut the kindergarten in Kashgar, saying it lacked the proper license.

Faced with bureaucratic intransigence to his proposed school in Urumqi, Mr. Ayup began documenting his odyssey online last spring, a move that most likely angered the authorities. “It was a kind of symbolic activism, to let people know how China was treating the status of the Uighur language,” said Mr. Juma, the childhood friend, who is a senior editor at Radio Free Asia, an American-financed news service.