The Problem With Dialogue in Historical Fiction

dialogue is something that then you have to balance very carefully in historical fiction and not only but all fiction. I don't write in colloquial English as it would have been used because people wouldn't understand it there's a famous case in the 1200s of a fight in Exeter High Street where French Norman speaking men started rioting. You cannot possibly write a book authentically as it would've been because it'll just be incomprehensible.