In setting my novel in 1930's Japan and China, I have struggled with deciding how to deal with dialogue/translation issues that would normally come up. Since my main characters (two protagonists who speak multiple languages) are the observers/narrators of the novel, I have chosen to not use Japanese/Chinese except in cases where a translation is not possible, or for an organization. Since it is historical fiction, would it being told in English hold it back?
Also, in order to be more accessible to the common reader, I have updated the dialogue style to a more modern style. Since my story is wholly fabricated, I feel I can take a bit more dramatic license. So long as the dialogue is well-written and effectively conveys the emotion/thoughts of the character, I don't worry too much about making sure it sounds like it's from the '30's.
Also, in order to be more accessible to the common reader, I have updated the dialogue style to a more modern style. Since my story is wholly fabricated, I feel I can take a bit more dramatic license. So long as the dialogue is well-written and effectively conveys the emotion/thoughts of the character, I don't worry too much about making sure it sounds like it's from the '30's.