Final answer:
The Great Vowel Shift was a gradual change in the pronunciation of certain vowels in the English language during the Middle English period.
Step-by-step explanation:
The Great Vowel Shift was a gradual change in the pronunciation of certain vowels in the English language during the Middle English period. It primarily affected the long vowels, causing them to shift their sound. For example, the vowel 'a' in words like 'name' and 'name' was pronounced as 'ah' in Middle English, but shifted to the sound we now pronounce as 'ay' in Modern English. Similarly, the vowel 'e' in words like 'bed' and 'red' was pronounced as 'eh' in Middle English, but shifted to the sound we now pronounce as 'ee' in Modern English.