I have worked as a translator for about 10 years. I am quite familiar with both american and british english idioms. I know its subtleties like something that helps a lot while making a more accurate translation. Not everyone is gifted with a talent to learn and understand perfectly a foreign language so, because of it a translator plays his role as a bridge to the reader unfamiliar with language of the original work. I know that tradutore traditore is what the italians say about translation but how could a brazilian reader be familiar with shakespeare plays or Goethes' masterpieces?