Alternatively, en-5 may be used to describe someone like me whose mother tongue isn't actually English (I was brought up in Hong Kong speaking Cantonese), but speaks with native fluency and a professional application (I teach Chinese immigrants English - a language teacher is a "typical" level-5 description, according to the Babel documentation). In some ways this is a wholly different definition of en-5: I only speak fluently two dialects of English (RP and Hong Kong), and can only understand a select few others.

Level-5 templates do mess up the system when used by someone like Kim, a native speaker who wants to highlight one's professional language skills, though.