Middle English is the name given by historical linguists to the diverse forms of the English language in use between the late 11th century and about 1470, when the Chancery Standard, a form of London-based English, began to become widespread, a process aided by the introduction of the printing press into England by William Caxton in the late 1470s.
The transfer of power in 1066 resulted in only limited culture shock. But the top levels of society of English-speaking political and ecclesiastical hierarchies were removed. Their replacements spoke Norman French and used Latin for administrative purposes. Thus Norman French came into use as a language of polite discourse and literature, and this fundamentally altered the role of Old English in education and administration.
The new English language did not sound the same as the old: for as well as undergoing changes in vocabulary, the complex system of inflected endings which Old English had was gradually lost or simplified in the dialects of spoken Middle English. This change was gradually reflected in its increasingly diverse written forms too. The loss of case-endings was part of a general trend from inflections to fixed word order that also occurred in other Germanic languages, so cannot be attributed simply to the influence of French-speaking sections of the population. English remained, after all, the language of the vast majority.
