(CNN)Ethnic Mongolian students and parents in northern China have staged mass school boycotts over a new curriculum that would scale back education in their mother tongue, in a rare and highly visible protest against the ruling Communist Party's intensified push for ethnic assimilation.
How China's new language policy sparked rare backlash in Inner Mongolia
Under the new policy, Mandarin Chinese will replace Mongolian as the medium of instruction for three subjects in elementary and middle schools for minority groups across the Inner Mongolia Autonomous Region, home to 4.2 million ethnic Mongolians.
Authorities have defended the adoption of a national standardized curriculum -- which comes with Chinese textbooks compiled and approved by policymakers in Beijing -- will improve minority students' paths to higher education and employment.
But parents fear the move will lead to a gradual demise of the Mongolian language, spelling an end for the already waning Mongolian culture.
To critics, the policy bears a chilling resemblance to measures rolled out in the regions of Tibet and Xinjiang, where Mandarin has replaced ethnic minority languages as the instruction language in most schools. It also reflects a shift in the Party's policy towards more aggressive assimilation under President Xi Jinping, as evident in the harsh crackdown on the mostly Muslim Uyghur minority in Xinjiang.
This week, as students across China returned to classrooms for the new school year, many ethnic schools in Inner Mongolia remained empty as parents refused to send their children back, according to residents and videos circulating online.
"We Mongolians are all against it," said Angba, a 41-year-old herder in Xilin Gol League whose 8-year-old son has joined the boycott.
"When the Mongolian language dies, our Mongolian ethnicity will also disappear," the father said. As with the other Mongolian residents who spoke to CNN for this article, Angba requested to use a pseudonym over fear of repercussions from authorities for speaking to foreign media.
Videos shared with CNN by overseas Mongolians and rights groups appear to show crowds of parents gathering outside schools -- sometimes singing Mongolian songs -- under the close watch of police officers, demanding to bring their children home. In one video, students in blue uniforms topple metal fences blocking a school entrance and rush outside. In another, rows of schoolchildren throw their fists in the air and shout: "Let us Mongolians strive to defend our own Mongolian language!" CNN is unable to independently verify the videos.
But the opposing voices have spread far beyond students and parents. According to residents, overseas Mongolians and rights groups, Mongolians across the region from musicians to members of the local legislature have allegedly signed petitions calling for the regional government to rescind the policy.
On Thursday alone, some 21,000 signatures were collected from residents in 10 counties, forming 196 petitions to the regional government's education bureau, according to an overseas Mongolian scholar who has been in close touch with local residents. In the regional capital of Hohhot, over 300 employees at a prominent regional television station also signed the petition, said the scholar, who has requested anonymity due to sensitivity of the issue.
On Weibo, China's version of Twitter, some ethnic Han users have spoken out in sympathy of Inner Mongolia's plight to protect its mother tongue. Some citizens in the neighboring country of Mongolia have also protested in solidarity.
A staff member at the Inner Mongolia regional government wouldn't comment when reached by phone by CNN on Thursday.
A readout of a regional government meeting on Tuesday said the rolling out of standardized textbooks shows "the loving care of the Party and the state towards ethnic regions" and benefits "the promotion of ethnic unity, the development and progress of ethnic regions, and the building of a strong sense of community for the Chinese nation."
On Thursday, China's foreign ministry dismissed reports of the protests in Inner Mongolia as "political speculation with ulterior motives."
"The national common spoken and written language is a symbol of national sovereignty. It is every citizen's right and duty to learn and use the national common spoken and written language," spokesperson Hua Chunyin said.
The boycotts and petitions are a rare show of open discontent among ethnic Mongolians, hailed by some as one of China's "model minorities" that have been largely pacified and successfully integrated into the ethnic Han majority.
Mongolians are one of only two ethnic minorities to have ruled imperial China. In the 13th century, the Mongol Empire arose from the unification of several nomadic tribes in the Mongolian steppes to conquer much of Eurasia -- including China, where it was known as the Yuan Dynasty (from AD 1271 to 1368).
After World War II, the Chinese Communist Party gained control of