Why did the London variation of English become the national standard?

London Standard English is the speech that came to be used throughout England after the fifteenth century, with occasional regional features interspersed. London had started out with its own dialect in the eleventh century, so local in nature that it differed even from that of Westminster, two miles to the west. By the fifteenth century its dialect had almost merged with all of the other East Midlands dialects, and a century later, it is only with assiduousness that one can find any non-London dialect forms in written texts. It is obvious what has happened. London has grown so important that its speech has become the speech of all England. The first shepherd in the Second Shepherds Play complains that Make the sheep-stealer affects a "Southern tooth.” Poor shepherd, all of his grandchildren will seem "southern-toothed" to him. By 1589 Puttenham advises that books should be written in the speech "of London and the shires lying about London within 60 miles, and not much above."  The use of London English has become a matter for precept as well as automatic habit.

When did this process of standardization occur? Moore states that by 1450 London speech was standard for public documents, and that by 1500 private correspondence shows few non-standard features. Still, Caxton, writing in 1490, complains that the language spoken in one shire varies from that of another so greatly that the most common words may be unintelligible.

Explanation:

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b) the confederacy had to pay all union war expenses.

profound political, administrative, and social changes in the british isles.