Free speech means the right vested on a person where by s/he can speak freely. Free speech also includes the right to write and publish ones own sentiments.
The following is an example of a state statute (Wisconsin) defining free speech.
According to Wis. Const. Art. I, § 3, every person may freely speak, write and publish his sentiments on all subjects, being responsible for the abuse of that right, and no laws shall be passed to restrain or abridge the liberty of speech or of the press. In all criminal prosecutions or indictments for libel, the truth may be given in evidence, and if it shall appear to the jury that the matter charged as libelous be true, and was published with good motives and for justifiable ends, the party shall be acquitted; and the jury shall have the right to determine the law and the fact.