The words cited, sighted, sited sound the same but have different meanings and spellings. Why do cited, sighted, sited sound the same even though they are completely different words?
The answer is simple: cited, sighted, sited are homophones of the English language.
Simple past tense and past participle of cite.
Having the ability to see.
Having eyesight of a specified kind. Often used in combination: keen-sighted.
Simple past tense and past participle of site.
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").