The words plaiting, plating sound the same but have different meanings and spellings. Why do plaiting, plating sound the same even though they are completely different words?
The answer is simple: plaiting, plating are homophones of the English language.
Present participle of plait.
A thin layer of metal, such as gold or silver, deposited on or applied to a surface.
A coating of metal sheets or plates.
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.