The Handbook
Roleplay Language
Nobody arrives knowing how to talk in character. The most common way a scene falls apart here is not trolling, it is somebody saying a perfectly reasonable sentence that belongs to the player rather than to the person they are playing. This page is the translation.
This page is guidance, not a rule. The rules it is built on are quoted below with their codes, and the rulebook stays the authority. Everything else here is phrasing: 27 things people actually say, and what to say instead.
Why it matters
Everyone in a scene is spending their evening on it. When one person steps outside the fiction, everybody else has to decide whether to pretend they did not hear it. That is the cost, and it is paid by the people around you rather than by you.
It is also the difference between a clip worth posting and a clip nobody can use. A scene where a bandit demands your purse is a story. The same scene with one sentence about skill tiers in it is a video game lobby, and no amount of editing gets it back.
None of this is about being good at improvising. It is vocabulary, and vocabulary is learnable in an evening.