Middle English is generally described as the language, and its various dialects, which emerged following the Norman Conquest of 1066 and lasted until the early sixteenth century (the completion of the Great Vowel Shift). The Great Vowel Shift which generally marks the end of Middle English was the systematic shift in the pronunciation of stressed long vowels in English which permanently changed the pronunciation of the language.
During the period of Middle English, England was essentially a trilingual culture: (1) French was the language of administration, culture, courtiership, and cuisine; (2) Latin was the language of church, education, and philosophy, and (3) English was the language of popular expression and personal reflection.
Historically, the first official text in English since the Conquest appeared in 1258 with a proclamation by Henry III (it is actually a translation of the French original). In 1362, parliament was addressed for the first time in English, though all records were kept in French. In the 1380s, John Wycliffe supervised the translation of the Bible into Middle English. In 1417 royal clerks began using English for official written documents, and by 1423 Parliament was keeping most of its records in English.
The Norman Conquest of England in 1066 involved an invasion of Norman French-speaking nobility and soldiers. The Norman Conquest brought a whole new vocabulary to the English language. Many of the French words that came into English at that time have endings such as –ion, -ioun, -ment, -encen, -aunce, -or, -our. Spellings that include –ei, -ey, -oy also indicate a borrowing from French.
In addition, the Norman Conquest also radically changed the stress pattern in sentences, and verbal constructions. Most of the French words that came into English were polysyllabic and the variation in stress changes the meaning. For example, reCORD is a verb, but REcord is a noun.
The change from Old English to Middle English involved the loss or simplification of noun case endings and the loss of adjective endings. In addition, grammatical gender was lost: nouns were no longer masculine, feminine, or neuter. These changes can be seen in the entries in the Peterborough Chronicle, a prose history kept by the monks in Peterborough Abbey. Each entry is a set of events of a given year and each entry begins with the phrase meaning “in this year.” In 1083, the monks wrote “on Pissum geare” in which the –um and –e signal a dative masculine singular. By 1154, they wrote “on Pis gear” in which the endings have completely disappeared.
The dual pronoun—that is, a pronoun indicating just two people—was lost. With Middle English, pronouns were either singular or plural.
In Middle English word order became standardized and the Subject/Verb/Object form became the standard for the simple declarative sentence.
In Middle English certain sound clusters underwent a metathesis in which the sounds were inverted. Thus “aks” became “ask”; “brid” became “bird”.
Middle English changed poetry. Old English poetry was alliterative in structure: the metricality of the poetic line was determined not by the number of syllables, rhyme, or classical meter, but by the number of alliterative words in stress positions. In alliteration there is a repetition of the initial consonant or vowel. By 1200, English writers were creating poetry in rhymed couplets. The earliest recorded Middle English poetry is The Owl and the Nightingale which was written about 1200.
While the dividing line between Middle English and Early Modern English is generally seen as the completion of the Great Vowel Shift which started in the middle of the fifteenth century and was completed by the middle of the sixteenth century, the change was also driven by technology: the increased use of the printing press. William Caxton started printing in Westminster in 1476.