The words faille, file, phial sound the same but have different meanings and spellings. Why do faille, file, phial sound the same even though they are completely different words?
The answer is simple: faille, file, phial are homophones of the English language.
A slightly ribbed, woven fabric of silk, cotton, or rayon.
A container, such as a cabinet or folder, for keeping papers in order.
A collection of papers or published materials kept or arranged in convenient order.
Computer Science A collection of related data or program records stored as a unit with a single name.
A line of persons, animals, or things positioned one behind the other.
A vial.
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.
If they are spelled the same then they are also homographs (and homonyms); if they are spelled differently then they are also heterographs (literally "different writing").