Or better - a responsibility. In California, our equivalent of the First Amendment says:

Every person may freely speak, write and publish his or her sentiments on all subjects, being responsible for the abuse of this right. A law may not restrain or abridge liberty of speech or press.

California Const. Art. I section 2, emphasis added.

In other words, you can say what you want, and the government won’t stop you from saying it, but you must bear the responsibility for the words you use.