The words pail, pale sound the same but have different meanings and spellings. Why do pail, pale sound the same even though they are completely different words?
The answer is simple: pail, pale are homophones of the English language.
A watertight cylindrical vessel, open at the top and fitted with a handle; a bucket.
The amount that a pail can hold.
A stake or pointed stick; a picket.
A fence enclosing an area.
The area enclosed by a fence or boundary.
A region or district lying within an imposed boundary or constituting a separate jurisdiction.
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.