structural:reformatting, linguistic:paraphrasing
Transition from Old English

The transition from Late Old English to Early Middle English had taken place by the 1150s to 1180s, the period when the Augustinian canon Orrm wrote what are widely regarded as the oldest surviving texts in Middle English, now called the Ormulum.

The influence of Old Norse aided the development of English from a synthetic language with relatively free word order to a more analytic language with a stricter word order. Both Old English and Old Norse (as well as the descendants of the latter, Faroese and Icelandic) were synthetic languages with complicated inflections. The eagerness of Vikings in the Danelaw to communicate with their Anglo-Saxon neighbours resulted in the erosion of inflection in both languages. Old Norse may have had a more profound impact on Middle and Modern English development than any other language. Simeon Potter says, "No less far-reaching was the influence of Scandinavian upon the inflexional endings of English in hastening that wearing away and leveling of grammatical forms which gradually spread from north to south."

Viking influence on Old English is most apparent in pronouns, modals, comparatives, pronominal adverbs (like "hence" and "together"), conjunctions, and prepositions show the most marked Danish influence. The best evidence of Scandinavian influence appears in extensive word borrowings, yet no texts exist in either Scandinavia or Northern England from this period to give certain evidence of an influence on syntax. However, at least one scholarly study of this influence shows that Old English may have been replaced entirely by Norse, by virtue of the change from the Old English syntax to Norse syntax. The effect of Old Norse on Old English was substantive, pervasive, and of a democratic character. Like close cousins, Old Norse and Old English resembled each other, and with some words in common, they roughly understood each other; in time, the inflections melted away and the analytic pattern emerged. It is most "important to recognise that in many words the English and Scandinavian language differed chiefly in their inflectional elements. The body of the word was so nearly the same in the two languages that only the endings would put obstacles in the way of mutual understanding. In the mixed population that existed in the Danelaw, these endings must have led to much confusion, tending gradually to become obscured and finally lost." This blending of peoples and languages resulted in "simplifying English grammar".

While the Old Norse influence was strongest in the dialects of the southern part of North (which formed part of Scandinavian York), the East Midlands and the East of England, which were under Danish control, words in the spoken language emerged in the 10th and 11th centuries near the transition from Old to Middle English. Influence on the written languages only appeared from the beginning of the 13th century, this delay in Scandinavian lexical influence in English has been attributed to the lack of written evidence from the areas of Danish control, as the majority of written sources from Old English were produced in Wessex (in the West Saxon dialect), the heart of Anglo-Saxon political power at the time.

The Norman Conquest of England in 1066 saw the replacement of the top levels of the English-speaking political and ecclesiastical hierarchies by Norman rulers who spoke a dialect of Old French, now known as Old Norman, which developed in England into Anglo-Norman. The use of Norman as the preferred language of literature and polite discourse fundamentally altered the role of Old English in education and administration, even though many Normans of this period were illiterate and depended on the clergy for written communication and record-keeping. A significant number of words of Norman origin began to appear in the English language alongside native English words of similar meaning, giving rise to such Modern English synonyms as pig / pork, chicken / poultry, calf / veal, cow / beef, sheep / mutton, wood / forest, house / mansion, worthy / valuable, bold / courageous, freedom / liberty, sight / vision, and eat / dine. The role of Anglo-Norman as the language of government and law can be seen in the abundance of Modern English words for the mechanisms of government that are derived from Anglo-Norman, such as court, judge, jury, appeal, and parliament. There are also many Norman-derived terms relating to the chivalric cultures that arose in the 12th century, an era of feudalism, seigneurialism, and crusading.

Words were often taken from Latin, usually through French transmission. This gave rise to various synonyms, including kingly (inherited from Old English), royal (from French, which inherited it from Vulgar Latin), and regal (from French, which borrowed it from classical Latin). Later French appropriations were derived from standard, rather than Norman, French. Examples of resultant cognate pairs include the words warden (from Norman) and guardian (from later French; both share a common ancestor loaned from Germanic).

The end of Anglo-Saxon rule did not result in immediate changes to the language. The general population would have spoken the same dialects as they had before the Conquest. Once the writing of Old English came to an end, Middle English had no standard language, only dialects that evolved individually from Old English.