Middle English / Modern English Vowels: AKA "The Great Vowel Shift," ca. 1400-1500 CE
To shift your long vowels backward in time from Modern to Middle English, move each one's sound forward and up into the next one's place (the sound for "e" becomes the sound for "a," the sound for "i" becomes the sound for "e," etc.). To see examples of the sounds in words, click here. To hear some examples of the before and after vowel sounds, click here.