"Your right to throw a punch stops where the other person's nose begins."

Your right to freedom of speech should stop where the other person's reasonable right to not hear filthy or vulgar language should start.

What you speak in public should be considered affecting that right and therefore there should be limits placed on insulting and vulgar language which shouldn't be used, especially around small children.

Private establishments are another story and dependent upon the owner, but using such speech intentionally against another person as a weapon meant to wound should always be considered crossing the limits.