"ea" pronunciation

[lats]

How come the word "sweat" is pronounced 'swett' whereas meat, treat, eat, feature all have the 'eet' sound?

[Quizmonster]

In Middle English, the word was spelt 'swet', so - despite the later alteration of spelling - it retained its pronunciation. English is awash with similar apparent anomalies.

[lats]

How about "read" as in "to read a book" and "i have read that book"?

[Quizmonster]

Again, in Middle English, the past tense was 'redde' or 'radde', so again that pronunciation was kept. Some writers did try to indicate the difference between the sound of past and present tenses by spelling the former as 'red', but it never caught on. Now, it probably never will!