As N.F.L. players’ protests during the national anthem continue, with Vice President Mike Pence’s departure from the Colts game this weekend reigniting the debate, and white nationalists again marching in Charlottesville, Va., on Saturday, parents and educators may find themselves trying to explain free speech to children.

Many school-age children across the country have adopted the players’ protest methods, and a few have faced consequences. Private high school students in Michigan knelt before their football game Friday despite prior warning of punishment, some private school students have recently been thrown off their teams for protesting, and other schools both public and private warned that punishment would follow any protests.

Experts say having informed and fact-based discussions about free speech can help children think through hot-button issues and decide how and when to use their own voices.

Adults might start by telling children that the term “free speech” covers all kinds of expression of opinions, even the kind without words. It may be useful to explain that in countries like North Korea, people who speak out against the government can be arrested. The right to free speech means that Americans may express their opinions without fear of punishment from the government — but that level of freedom isn’t always extended to school-age kids.

Legal guidance on student’s rights comes from a landmark 1969 Supreme Court ruling in a case called Tinker v. Des Moines Independent Community School District, involving public students protesting the Vietnam War by wearing black armbands to school. The court ruled that students do not “shed their constitutional rights to freedom of speech or expression at the schoolhouse gate.”

Based on that decision, students are allowed to express themselves freely unless what they say causes a “substantial disruption” of the school environment or interferes with the rights of others.

At Evanston Township High School in Illinois, actions during the national anthem became a schoolwide discussion after their girls’ volleyball team collectively knelt at a game a few weeks ago, the school superintendent Eric Witherspoon said. As school band members worked through their own choices later that week, Mr. Witherspoon assured the students and parents that non-disruptive protests would not be punished, and that the school considered kneeling an allowed free speech demonstration.

But he encouraged students to ask themselves, “Are they doing something as a copycat or are they doing something as a purpose?” In the end about half the band knelt during the anthem, Mr. Witherspoon said.

Focus on Law, Not Politics

Frame the discussion from a constitutional perspective rather than a political one, said Jeffrey Rosen, president and chief executive of the nonpartisan National Constitution Center in Philadelphia.

“Don’t debate whether or not people should salute the flag or should kneel or stand during the national anthem,” Mr. Rosen said, suggesting parents instead focus on what the free speech clause of the First Amendment allows people to do.

Despite contentious debate on how free speech rights are utilized, Mr. Rosen said, both conservative and liberal scholars generally agree on what free speech is under the law, including that United States citizens acting peacefully can express their opinions, even unpopular or offensive ones, without interference from the government. That includes protection for so-called “hate speech” that attacks someone’s race, religion or sexual orientation.

Make It Relatable

It’s important that students understand how far free speech rights extend in their own world, and that there are limits to what is covered. “The government can’t limit your free expression; your parents can,” and so can your school, said Barbara McCormack, the vice president of education at the Newseum in Washington, which educates thousands of students each year on the First Amendment.

Even though Americans are free to hold up protest signs on the National Mall criticizing a new law, public schools can limit speech they deem disruptive, and private schools have even more say on what their students can do.

Educators also suggest explaining that free speech rights do not allow words or actions that would lead to immediate harm. For many children, “harm” in the realm of free speech is confusing. “They get into feelings, so we have to separate those,” Ms. McCormack said. Educators should explain, she said, that saying, “Susie is ugly,” is not nice, but it’s not banned under the Constitution. Instead, to be prohibited, speech must be likely to incite immediate harm, like “We don’t like redheads. Here’s one now — let’s get them,” Ms. McCormack said. Individual states’ anti-bullying laws may help clarify what is considered over the line.

Add Historical Context

To explain free speech in action, parents can use examples of protest movements historically, perhaps with events children are already somewhat familiar with, like Rosa Parks’s refusal to give up her seat on the bus or Martin Luther King’s “I Have a Dream” speech.

Arrests of civil rights leaders and setbacks during the movement also provide another important free speech lesson. “It’s not always smooth sailing and a straight trajectory to your change,” Ms. McCormack said, and it teaches students that, “Sometimes your rights are violated, even when you’re trying to exercise them.”

Talk About Speaking Up

Conversations about free speech can offer opportunities to encourage children to think of what they care about and when they might want to speak up. The Newseum asks middle school students to choose any subject important to them, be it loving their own curly hair or protecting animals, and have them write messages about it on a label for a water bottle or a sticker for their iPhone case.

It can be helpful to highlight other activities children can participate in outside of school, like joining local demonstrations or marches, writing letters to their lawmakers, and volunteering their time or raising money to support causes they care about.

Schools’ anti-bullying policies can be an entry point for discussing how children might speak up, said Jane Kirtley, a professor of media ethics and law at the University of Minnesota.

“You don’t have to sit by while someone is being bullied, and you don’t have to sit back while someone is saying something that’s not appropriate,” she said.