The words tails, tales sound the same but have different meanings and spellings. Why do tails, tales sound the same even though they are completely different words?
The answer is simple: tails, tales are homophones of the English language.
Plural form of tail.
Short for tailcoat.
The side of a coin that doesn't bear the picture of the head of state or similar
tailings; waste
A group of people summoned to fill vacancies on a jury that has become deficient in number.
The writ allowing for a summons of jurors.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License, 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").