The words bay, bey sound the same but have different meanings and spellings. Why do bay, bey sound the same even though they are completely different words?
The answer is simple: bay, bey are homophones of the English language.
A body of water partially enclosed by land but with a wide mouth, affording access to the sea: the Bay of Biscay.
An area of land, such as an arm of prairie partially enclosed by woodland, that resembles in shape or formation a partially enclosed body of water.
Architecture A part of a building marked off by vertical elements, such as columns or pilasters: an arcade divided into ten bays.
Architecture A bay window.
A provincial governor in the Ottoman Empire.
A ruler of the former kingdom of Tunis.
Used as the title for such a ruler.
Used formerly as a title for various Turkish and Egyptian dignitaries.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.