Meyer v. Nebraska was a case that went to the Supreme Court of the United States a long time ago. It was about a man named Robert Meyer who was a teacher, and he was teaching a kid named Erich some German language in school. But in Nebraska, there was a law that said it was illegal to teach any other language except English in the public schools. So the school district fired Mr. Meyer because he violated the law.
Mr. Meyer was not happy with what happened, so he went to court and said that the law was not fair because it violated his right as a teacher to teach whatever he wanted. And also, it violated the kid's right to learn other languages. The court agreed with Meyer and declared that the law was unconstitutional.
So, the important thing to remember is that the court decided that teachers and students have the constitutional right to teach and learn any language they want. It is called the "liberty of teaching" and "learning" and is protected by the First Amendment to the U.S. Constitution. This case also showed that state laws are not allowed to restrict these rights unless there is a very good reason to do so.