Look at this quotation from Chomsky:
"Linguistic theory is concerned with an ideal speaker-listener in a completely homogeneous speech community"
Chomsky, N. (1965) “Aspects of the theory of syntax” MIT Press
Variationist theories on the other hand, believe that variation has to be present at all stages of description. How useful are the idealised and variationist models when it comes to teaching English to speakers of other languages?
For the first time in weeks I think I'm starting to get my head around what this question is asking, but I thought I'd throw it open to the public and gauge my answer in relation to the answers this post gets.