Here's a breakdown:
* Origin: The word "quay" comes from the Old French word "cai," meaning "wharf."
* French Pronunciation: In Old French, the "ai" was pronounced like the "ay" in "say."
* English Adoption: When English adopted the word, the pronunciation shifted. The "ai" sound evolved into the "e" sound in many English words, similar to how "day" became "day" and "say" became "say."
* Influence of "Key": It's possible that the change in pronunciation was also influenced by the similar-sounding word "key," which was already present in English. This is a common phenomenon in language, where words that sound alike can influence each other's pronunciation over time.
So, while the spelling might appear to suggest a pronunciation closer to "kway," the historical evolution of the language led to its current pronunciation as "key."