Why English vowels don't sound like their letters
Many people learning English, used to how the letter i sounds in Spanish or Italian, read the word bite as something like beet. That isn't really a mistake about English. It is close to how the word sounded in late Middle English.
Over roughly three centuries, starting in southern England, the long vowels of English moved, one after another. The Danish linguist Otto Jespersen named the change the Great Vowel Shift in a grammar published in 1909, and drew the first diagram of it.
The pattern works like a chain. Long vowels made with the tongue in the middle of the mouth moved higher. The two highest ones, the ee sound and the oo sound, had nowhere higher to go, and became two-part sounds, the diphthongs we now hear in bite and out.
Meanwhile, spelling was settling. Standard English spelling began to form in the 15th and 16th centuries, right in the middle of the change, and it did not follow the sounds. So the letters kept recording older vowels. Meet and meat, for example, once had different vowels, which is why they are spelled differently. They only came to sound the same later.
German went through similar vowel changes a little earlier, and its spelling was adjusted to match. English never made that adjustment, which is why its vowel letters so often seem to point somewhere other than where speakers actually go.
Exactly how the shift unfolded is still debated. Some linguists argue that the middle vowels rose first and pushed the highest ones out of their place. Others argue that the highest vowels moved first, and the rest moved up to fill the gap. Either way, the result is the same.
Each time you write bite and say something else, you are using a spelling made for an older pronunciation of the word.
Which pair of words had different vowels before the shift but sound the same today?
English spelling often records how words sounded before the Great Vowel Shift, which is why its vowel letters seem to say the wrong thing.
