Ahh yes, the old "you can't yell fire in a crowded theater" bit. That can be argued against. Such as:
You can if it is part of a play.
You can if the crowd knows about it in advance.
You can if there is crowd participation.
You can if there is a fire.
and oh so much more. There is no law stating that you can't yell fire in a crowded theater. As you stateed laws can be enacted to ensure that that right does not endanger or infringe of the rights of others; that does not mean that they can ban certain words from being spoken or to require expensive "licenses" to use such words.
No, the law would state that no actions can be taken including the use of language to endanger others. That would cover your crowded theater scenario. And yes, licenses are required for all sorts of activities exercised under the guise of the 1st Amendment, including licenses to print and sell books, licenses for journalists, licenses for broadcasting. All libel and slander laws are designed to curb the use of speech, whether written or verbal.