This works on Lost for me - i.e. when Sun and Jin talk to each other, we get the conversation subtitled, whereas when we're in the pov of one of the American characters, there are no subtitles. But if the entire film is set in a non-English speaking country, be it Germany or Russia or, well, the ancient Graeco-Roman world? With no English or American character present? Why should there be subtitles? Assuming that the actors aren't native German/Russian/whatever speakers, of course. Wasn't there a British tv movie about the Wannsee conference a couple of years ago? I don't think anyone spoke German or German-accented English in that one, which made sense since none of the actors was German and it was clear where the action took place anyway.