I prefer subtitles to dubbing because something always get lost in translation; with subtitles you can at least try to connect the dots if you have some most basic knowledge or at least a word or two of the language spoken on the screen.

Sometimes film makers don't have much of choice of using English (or their country's) language instead of authentic languages supposed to be spoken by characters on the screen. Any film set in Ancient Egypt, for example, would have trouble reconstructing what Ancient Egyptian sounded like (we know meaning the hieroglyphs, but actual pronounciantion of the words is still matter of debate about linguists). British English, on the other hand, can be used due to its strong regional variety, as well as a sign of social stratification - upper class characters are supposed to speak Received Pronounciation (or King's English), while lower class characters speak with heavy Cockney or Northern English accents. In Classic Hollywood there were attempts for characters to mark their upper class (or sophistication) with so-called Mid Atlantic accent that would separate them from ordinary working class characters that spoke like people on the streets of New York.