From Wikipedia, the free encyclopedia.
The Great Vowel Shift was a major change in the pronunciation of the long vowels of the English language (i.e. a vowel shift), which began in the 15th century and was mostly completed in the 16th century, although it continued for some time after that.
The values of the long vowels form the main difference between the pronunciation of Middle English and Modern English. Originally, they were essentially the same as those found in Latin. However, during the Great Vowel Shift, the two highest long vowels became diphthongs, and the other five underwent an increase in tongue height and one of them came to the front.
The principal changes are roughly the following, though of course exceptions occur, the transitions were not always complete, and there were sometimes accompanying changes in orthography:-
- /a:/ -> /ei/ (in e.g. make)
- /e:/ -> /i:/ (in e.g. feet)
- /i:/ -> /ai/ (in e.g. mice)
- /o:/ -> /u:/ (in e.g. boot)
- /u:/ -> /au/ (in e.g. mouse)