STANDARD ENGLISH, STANDARD. The Columbia Guide to Standard American English. 1993
Every commentator on usage eventually comes back to these two terms and to what is or is not Standard, even though, despite its many objectively measurable qualities, any definition of Standard English is partly subjective. Ideally, Standard English is the language acceptable and normative among reputable people in reputable circumstances—the prestige dialect recognized throughout the area and populations to whom the standard applies.
One can argue, for example, that there are indeed grammatical constructions and senses of words that are universally accepted wherever and by whomever English is spoken. One can then say that they are Standard English, in that everybody who is anybody uses, accepts, and approves them. Certainly few who meet that standard will accept deviations from it by others who claim to be their social equals. And when Standard speakers converse, most will deliberately use locutions proscribed by Standard English only if they are absolutely certain that their listeners will know they know better; if there is any chance that anyone will think the usage inadvertent, few will take the risk just to get a laugh.
But obviously Standard American, Standard British, Standard Australian, and Standard Canadian English differ from each other in many particulars. And in some particulars, Boston Standard differs from that of New Orleans. This is clear to anyone who travels, goes to the movies, or listens to radio or television. It is also clear that there are differences within each of these regional dialects, and that the acceptability of one feature or another also may vary, depending upon who is calling the shots. STANDARD ENGLISH, STANDARD. The Columbia Guide to Standard American English. 1993