HIGHLAND PARK, Ill. (CBS) — Students from a north suburban high school are taking part in a march and rally Friday afternoon against the use of the “r-word.”

WBBM Newsradio’s Mike Krauser reports Highland Park High School’s event is part of the national Spread the Word to End the Word campaign to encourage people to stop using the word “retard” to describe people with developmental disabilities, or to disparage others.

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Students and staff at the school are being encouraged to wear t-shirts honoring the campaign and to talk about why the movement is important.

The march will begin after school lets out and organizers are encouraging students’ families and other community members to join in. They will march from the school to Nova HP, a local youth center.

LISTEN: WBBM Newsradio’s Mike Krauser reports

Highland Park High School special education teacher Melissa Zientara said criticism of the 2008 film Tropic Thunder, which used the word more than 24 times, really started the campaign to end use of the word retard.

“It wasn’t just used in the movie, Ben Stiller actually played a person with a disability, and it was so absolutely offensive and disrespectful,” she said.

In the film, Stiller plays an actor who starred in a movie called “Simple Jack,” about a man with an intellectual disability. Other characters in Tropic Thunder repeatedly ask him to reenact the movie and Robert Downey Jr.’s character criticizes him for “going full retard” in his portrayal of the disabled character.

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Special Olympics Chairman Timothy Shriver was among many advocates for the disabled who called for a boycott of Tropic Thunder when it was released.

The Special Olympics is one of the biggest supporters of the campaign to end the use of a word heard everywhere from the playground to the White House.

When Mayor Rahm Emanuel was the White House chief of staff, he found himself apologizing to Shriver for calling liberal activists “f—ing retards” during a private meeting.

Shriver called use of the word “retard” hate speech, saying it disparages the 3.5 million athletes who have participated in the Special Olympics.

“The word retard has become the symbol of the idea that they don’t count,” he said.

Zientara has been teaching kids with disabilities for 14 years. Her students produced a video shown to other students, urging them to stop using the word.

“It’s absolutely insulting to all people with disabilities, and I don’t think a lot of people realize how insulting it is,” she said.

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She said kids in her peer mentoring class came up with the idea for Friday’s march and rally.