A Texas high school is investigating an incident after a video of a substitute teacher telling a student to “speak English” because he is in America gained traction online.

Carlos Cobian, a junior at Socorro High School in El Paso, told KVIA-TV that he was watching a soccer game between Argentina and Uruguay on his cellphone as he walked into class when the teacher asked him to hand over the device.

Cobian said he responded “Por qué?” — which means "why" in Spanish — because he was confused as to why he was being singled out when most of his classmates were also on their phones. Students are allowed to use cellphones in class with their teacher’s permission, according to school policy, but Cobian said the other student weren't asked to hand in their devices.

In the video, the unidentified white teacher can be heard chastising Cobian for speaking Spanish, telling him to “speak English. We’re in America.”

“I was shocked and then I got a little mad,” Cobian told KVIA-TV. “I thought it was a little racist because you know we live on the border … For her to come to teach at Socorro, being a sub, like 90 percent of the students here are Mexicans and Latinos.”

More than 80 percent of the population in El Paso identifies as Latino, according to census data. The border town was also the site of a massacre in August, that left 22 people dead; the gunman told authorities he was targeting Mexicans.

Cobian also said that following the incident, the teacher called the school’s security personnel, who questioned him.

“She actually tried to say that I pushed her, but I didn't and some of the videos come out [show]that I didn't really push her,” Cobian told KVIA-TV.

In an email to NBC News, Daniel Escobar, the chief communications director of the Socorro Independent School District, wrote that the incident is being investigated.

“Appropriate action, per our employee code of conduct policies, will be taken,” he wrote.

The League of United Latin American Citizens, or LULAC, which bills itself as the largest and oldest Latino organization in the United States, is calling for the substitute teacher to be “permanently disqualified from instructing students following racist remarks.”

“Teachers and all school staff are meant to be leaders and mentors to our children — not racists who harbor anti-immigrant sentiments,” Domingo Garcia, LULAC national president, said in a statement. “From 1918 until the Texas Bilingual Act in 1969, Texas laws banned Spanish in public schools and many of us remember personally that this was enforced with humiliating corporal punishment in schools.”

This is far from the first time a teacher has come under fire for mandating students speak English in recent years. In 2017, a group of New Jersey high school students staged a walkout after their teacher instructed them that U.S. soldiers are "not fighting for your right to speak Spanish — they're fighting for your right to speak American."

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