English is a West Germanic language that developed in England and south-eastern Scotland during the Anglo-Saxon era. As a result of the military, economic, scientific, political, and cultural influence of the British Empire during the 18th, 19th, and early 20th centuries, and of the United States since the mid 20th century, it has become the lingua franca in many parts of the world, and the most prominent language in international business and science. It is used extensively as a second language and as an official language in Commonwealth countries and many international organizations.

Historically, English originated from several dialects, now collectively termed Old English, which were brought to the eastern coast of the island of Great Britain by Anglo-Saxon settlers beginning in the 5th century. English was further influenced by the Old Norse language of Viking invaders.

At the time of the Norman conquest, Old English developed into Middle English, borrowing heavily from the Norman (Anglo-French) vocabulary and spelling conventions. The etymology of the word "English" is a derivation from the 12th century Old English englisc or Engle, plural form Angles ("of, relating to, or characteristic of England").

Modern English developed with the Great Vowel Shift that began in 15th-century England, and continues to adopt foreign words from a variety of languages, as well as coining new words. A significant number of English words, especially technical words, have been constructed based on roots from Latin and Greek.