How can a teacher manage a multitude of discourse and dialects to increasingly diverse classrooms

I feel truly passionate about his because English is my second language. I am troubled with the possibility of an ever changing discourse styles (code-switching) in the classroom. I would like to look further into it. Yes, teaching kids to code-switch is important. Using one's discourse is also quite okay when the audience is of the same discourse. But, could a teacher trying to manage all types of "codes" in a classroom, or should I say, could a teacher allowing all types of codes in the classroom be allowing for a continuation of possible "incorrect" forms of "standard English". For instance, would a discussion with many different codes become distracting to students? Acceptable, yes. In an English classroom? I am not quite convinced. In a blog, yes! In classroom discussions? I am not quite sure. Had I been exposed to many codes while learning English, would I have been learning the incorrect "standard English"? And, if I was, then how difficult would it have been for me to learn the standard? If the classroom is not where standard English is a must, then where is the learning place to learn standard English?

I still am quite confused about all this and need more time to think about it.