What significant linguistic event occurred during the Great Vowel Shift?

The Great Vowel Shift was a major change in the pronunciation of the English language that took place primarily between the 15th and 18th centuries. During this period, long vowel sounds underwent systematic shifts: for instance, the pronunciation of vowels that were once pronounced in a more open, continental style transitioned to higher, more closed sounds. This change is significantly evidenced by the way words that once had certain vowel sounds began to be pronounced differently, affecting the entire phonetic landscape of English.

This shift explains why the answer highlighting the change in vowel pronunciation is correct, as it encapsulates the essence of what occurred during this historical linguistic event. The impact of the Great Vowel Shift reshaped the pronunciation of English significantly, laying the groundwork for much of modern English phonology and contributing to the language's evolution over time. Thus, the focus on how vowel pronunciation changed directly aligns with the transformations that defined this pivotal moment in English linguistic history.