Speech crimes are certain kinds of speech that are criminalized by promulgated laws or rules. Criminal speech is a direct preemptive restriction on freedom of speech, and the broader concept of freedom of expression.
Laws vary by country in accordance with the legal principles that form the basis of their system of jurisprudence. Prohibitions on shouting fire in a crowded theater (as a practical joke, not as a warning) are not considered controversial in any country, given the potential for imminent harm.