The Great Vowel Shift was a major change in the pronunciation of the English language that occurred primarily between the 15th and 18th centuries. During this period, the long vowels of Middle English began to be pronounced higher in the mouth, leading to significant alterations in how words were spoken. For example, the vowel sound in the word bite shifted from a sound similar to "ee" to the modern "ai" sound. This shift contributed to the differences between Middle English and Modern English, affecting the way many words are pronounced today. It also played a role in the development of regional accents and dialects within the English language. The Great Vowel Shift is a key event in the history of English linguistics and helps explain some of the complexities in English spelling and pronunciation.