I think your question is not easy to answer. What we call 'standard' change day by day. For example, we used to think that to answer the question "how are you?" people have to say "I'm well" or " I'm fine";however, if you are in USA, you will see that people often use "I'm good !" :x . Who is wrong here ?
In addition, if you usually listen to news in English, you will also see that the pronunciation of English words changes drammatically.
Languages are easy to change !
As for me, "standard English is simply the English which is widely used, and is understood by every English speaker". Am I right ?
Sorry if I have too many spelling mistakes