Standard English is that variety of English which is usually used in print,and which is normally taught in schools and to non-native speakers learning the language.It is also the variety which is normally spoken by educated people and used in news broadcasts and other similar situations.The difference between standard and non-standard,it should be noted,has nothing in principle to do with differences between formal and informal language:Standard English has informal as well as formal variants. Historically the standard variety of English is based on the London Dialect of English that developed after the Norman Conquest resulted in the removal of the Court from Winchester to London.This dialect became the one preferred by the educated,and it was developed and promoted as a model,or norm,for wider and wider parts of society.It was also the norm that was carried overseas.But not one unaffected by such export.Today,standard English is codified to the degree that the grammar and vocabulary of English are much the same everywhere in the world where English is used:difference among the local standards is really quite minor,so that the Singapore,South Africa,and Irish varieties are really very little different from one another so far as grammar and vocabulary are concerned.Indeed,standard English is so powerful that it puts a tremendous pressure on all local varieties,to the degree that many of the long-established dialects of England have lost much of their vigor and there is much pressure on them to converge towards the standard.This latter situation is not unique to English:it is also in other countries where processes of standardization are under way.But it sometimes creates problems for speakers who try to strike some kind of compromise between local norms and national,even super-national ones. In terms of grammar and vocabulary,standard English_.
differs greatly from dialects in the U.K differs little from any variety of English in the world differs greatly from dialects outside the U.K differs a little from any variety of English