Which statement best summarizes why the government sometimes places limits on the first amendment right to freedom of speech?

There's a thing called protected speech, this is from an article called, "freedom of speech"

          When the government tries to regulate or punish any kind of communication, a number of questions must be answered to determine if the controls will survive a constitutional challenge.  The most basic is whether the conduct to be controlled qualifies as “speech.”

   " This is not as simple as it may seem.  Numerous activities that do not involve the use of words have been held to be speech, while in some cases, use of language, both written and oral, may not be considered speech.  Examples of expressive conduct that have been held to be speech are wearing black armbands or burning the American flag to protest the Vietnam war.  Although no words are spoken, the acts themselves are intended to communicate ideas and may be given the same protection as actual words.       On the other hand, the government may punish painting words on a public building (graffiti), or threatening to reveal damaging secrets if not paid (blackmail), even though that conduct involves written or spoken words."

Hope you can read this and find what you need! :)