How does Quentin Tarantino or any other screenwriter write dialog for a language he doesn't speak? I have never found any mention of Tarantino being able to speak in any language other than English.
In Quentin Tarantino's Inglourious Basterds, Hans Landa speaks English, German, French, and Italian fluently. In fact, about a third of the film is non-English and is subtitled.
I have never heard anyone who speaks German, French, or Italian complaining that their language was written by a hack.
Is the language written in English first and then rewritten in the appropriate language? Or does he work with other writers as he is writing it? Did he learn the basics of other languages to write for those languages?