The words ales, ails sound the same but have different meanings and spellings. Why do ales, ails sound the same even though they are completely different words?
The answer is simple: ales, ails are homophones of the English language.
Plural form of ail.
Third-person singular simple present indicative form of ail.
Plural form of ale.
Definitions from Wiktionary, Creative Commons Attribution/Share-Alike License and Wordnik.
Homophones (literally "same sound") are usually defined as words that share the same pronunciation, regardless of how they are spelled.