What Does "Freedom of Speech" Mean in the U.S.?

What is free speech? How does the freedom of speech factor into the U.S. Constitution? What are the limitations and protections of free speech in the U.S.?

The First Amendment guarantees freedom of speech. Freedom of speech gives Americans the right to express themselves without having to worry about government interference. It’s the most basic component of freedom of expression. The U.S. Supreme Court often has struggled to determine what types of speech is protected. Legally, material labeled as obscene has historically been excluded from First Amendment protection, for example, but deciding what qualifies as obscene has been problematic. Speech provoking actions that would harm others—true incitement and/or threats are also not protected, but again determining what words have qualified as true incitement has been decided on a case-by-case basis.