You can't say that

Indeed, freedom of speech does not exist anywhere, for every community on earth forbids the use of certain sounds, words, and sentences in various speech situations.

Peter Farb, Word Play

Peter Farb

Peter Farb makes the point that when it comes to freedom of speech, culture is much more restrictive than government.

All of us all of the time must watch our language. There are words we might use with our friends that we would not use in front of our mother. Or pastor, Or boss. 

There is jargon we use routinely in our jobs that we don't take home with us. And there is language we use when speaking with our small children at home we dare not use at work.

There are things we may say to a spouse or a lover that we would never say to anyone else. And vice versa. One of the gags often used on the ad libbed TV show Whose Line Is It Anyway? involves things you can say about your house or your car or whatever that you can't say about your significant other. It's always funny. And always true.

Mere civility and politeness prevents us from telling people what we we really think about them.

Some things we cannot say because they are too personal, too painful.

Most censorship is, in fact, self-censorship.