Transition from Old English
The transition from Late Old English to Early Middle English occurred at some point during the 12th century.
The influence of Old Norse aided the development of English

The main changes between the Old English sound system and that of Middle English include:
• Emergence of the voiced fricatives /v/, /ð/, /z/ as separate

With the discontinuation of the Late West Saxon standard used for the writing of Old English in the period prior to the Norman Conquest, Middle English

• Medulla Grammatice (collection of glossaries)
• Middle English creole hypothesis
• Middle English Dictionary
• Middle English literature

Nouns
Middle English retains only two distinct noun-ending patterns from the more complex system of inflection in Old English:

Most of the following Modern English translations are poetic sense-for-sense translations, not word-for-word translations.

• A. L. Mayhew and Walter William Skeat. A Concise Dictionary of Middle English from A.D. 1150 to 1580
• Middle English Glossary
• Oliver Farrar Emerson, ed. (1915). A Middle English Reader.