Middle English – from the late 11th to the late 15th century

For centuries following the Norman Conquest in 1066, the Norman kings and high-ranking nobles spoke one of the French langues d'oïl, that we call Anglo-Norman, a variety of Old Norman used in England and to some extent elsewhere in the British Isles during the Anglo-Norman period and originating from a northern langue d'oïl dialect. Merchants and lower-ranked nobles were often bilingual in Anglo-Norman and English, whilst English continued to be the language of the common people. Middle English was influenced by both Anglo-Norman and, later, Anglo-French (see characteristics of the Anglo-Norman language).

In this period, the French language was regarded like an official language in England, but this tendency would disappear in the 14th century.^[10]

Even after the decline of Norman-French, standard French retained the status of a formal or prestige language—as with most of Europe during the period—and had a significant influence on the language, which is visible in Modern English today (see English language word origins and List of English words of French origin). A tendency for French-derived words to have more formal connotations has continued to the present day. For example, most modern English speakers consider a "cordial reception" (from French) to be more formal than a "hearty welcome" (from Germanic). Another example is the rare construction of the words for animals being separate from the words for their meat, e.g., beef and pork (from the French bœuf and porc) being the products of "cows" and "pigs"—animals with Germanic names.

English was also influenced by the Celtic languages it was displacing, especially the Brittonic substrate, most notably with the introduction of the continuous aspect (to be doing or to have been doing), which is a feature found in many modern languages but developed earlier and more thoroughly in English.^[11]

While the Anglo-Saxon Chronicle continued until 1154, most other literature from this period was in Old Norman or Latin. A large number of Norman words were taken into Old English, with many doubling for Old English words. The Norman influence is the hallmark of the linguistic shifts in English over the period of time following the invasion, producing what is now referred to as Middle English.

English literature reappeared after 1200, when a changing political climate and the decline in Anglo-Norman made it more respectable. The Provisions of Oxford, released in 1258, was the first English government document to be published in the English language after the Norman Conquest. In 1362, Edward III became the first king to address Parliament in English. By the end of the century, even the royal court had switched to English. Anglo-Norman remained in use in limited circles somewhat longer, but it had ceased to be a living language.

Opening prologue of The Wife of Bath's Tale Canterbury Tales.

Geoffrey Chaucer is the most famous writer from the Middle English period, and The Canterbury Tales is his best-known work. Although the spelling of Chaucer's English varies from that of Modern English, his works can be read with minimal assistance.

The English language changed enormously during the Middle English period, both in grammar and in vocabulary. While Old English is a heavily inflected language (synthetic), an overall diminishing of grammatical endings occurred in Middle English (analytic). Grammar distinctions were lost as many noun and adjective endings were leveled to -e. The older plural noun marker -en largely gave way to -s, and grammatical gender was discarded. Approximately 10,000 French (and Norman) loan words entered Middle English, particularly terms associated with government, church, law, the military, fashion, and food.^[12]

English spelling was also influenced by Norman in this period, with the /θ/ and /ð/ sounds being spelled th rather than with the Old English letters þ (thorn) and ð (eth), which did not exist in Norman. These letters remain in the modern Icelandic alphabet, having been borrowed from Old English via Western Norwegian.