Great Vowel Shift

The Great Vowel Shift was a major change in the pronunciation of the English language that took place in England between 1350 and 1600. Through the Great Vowel Shift, all Middle English long vowels changed their pronunciation. English spelling was becoming standardized in the 15th and 16th centuries, and the Great Vowel Shift is responsible for many of the peculiarities of English spelling.

The Great Vowel Shift was first studied by Otto Jespersen (1860–1943), a Danish linguist and Anglicist, who coined the term.

The main difference between the pronunciation of Middle English in the year 1400 and Modern English (Received Pronunciation) is in the value of the long vowels. Long vowels in Middle English had "continental" values, much like those in Italian and Standard German, but in standard Modern English, they have entirely different pronunciations. The change in pronunciation is known as the Great Vowel Shift.

This timeline shows the main vowel changes that occurred between late Middle English in the year 1400 and Received Pronunciation in the mid-20th century by using representative words. The Great Vowel Shift occurred in the lower half of the table, between 1400 and 1600. The changes that happened after 1600 are not usually considered part of the Great Vowel Shift proper. Pronunciation is given in the International Phonetic Alphabet:

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