Freedom of speech though in the U.S. is severally limited by context. And it is the government that cannot impede freedom of speech. Employers, private schools, businesses and many other places can curtail free speech.
http://www.businessweek.com/articles...-the-workplace
Servicemen and women are also severally limited by what they can say or do while in the service.
http://www.uscourts.gov/EducationalR...peechMean.aspx
http://www.law.cornell.edu/wex/first_amendment