/period-languageChecks dialogue and action against the era you are writing in — vocabulary that had not entered the language yet, idioms from the wrong decade, objects and references that did not exist, and regional speech that does not match the place. It recognizes deliberate anachronism rather than flagging your choices back at you.
Run one focused pass
Period Language & Cultural Accuracy
One screenplay. One specialist lens. A result you can review where you write.
Parameters you can set when you run /period-language.
Practical answers before you run the pass.
Yes. Flashback and multi-era scripts are checked per era rather than against a single date, so a 1970s frame and a 1940s flashback are each judged on their own terms.
The pass has an explicit recognition step for it. Stylised or knowingly modern language in a period setting is treated as a choice, not an error.