A speech code is any rule or regulation that limits, restricts, or bans speech beyond the strict legal limitations upon freedom of speech or press found in the legal definitions of harassment, slander, libel, and fighting words. Such codes are common in the workplace, in universities, and in private organizations. The term may be applied to regulations that do not explicitly prohibit particular words or sentences. Speech codes are often applied for the purpose of suppressing hate speech(a postmodern term) or forms of social discourse thought to be disagreeable to the implementers.( it important to note the supreme court has voted unanimously that hate speech does not exists)
Use of the term is in many cases valuative; those opposing a particular regulation may refer to it as a speech code, while supporters will prefer to describe it as, for example and depending on the circumstances, a harassment policy. This is particularly the case in academic contexts. The difference may be ascertained by determining if the harassment policy bans more than what is legally defined as harassment; one that does is almost certainly a speech code.
In the United States, the Supreme Court has not issued a direct ruling on whether speech codes at public universities are unconstitutional. However, the United States District Court for the Eastern District of Michigan has struck down a speech code at the University of Michigan, indicating that broad speech codes seeking to prohibit hate speech probably violate the First Amendment (Doe v. University of Michigan, 1989). Subsequent challenges against such language supposedly couched in harassment policies, diversity mandates, and so forth instead of being self-identified as speech codes have generally succeeded to date.