sentences:  Mid and open vowels were raised, and close vowels were broken into diphthongs.For example, the word "bite" was originally pronounced as the word "beet" is today, and the second vowel in the word "about" was pronounced as the word "boot" is today.The Great Vowel Shift explains many irregularities in spelling since English retains many spellings from Middle English, and it also explains why English vowel letters have very different pronunciations from the same letters in other languages.