The words weald, wheeled, wield sound the same but have different meanings and spellings. Why do weald, wheeled, wield sound the same even though they are completely different words?
The answer is simple: weald, wheeled, wield are homophones of the English language.
Chiefly British A woodland.
Chiefly British An area of open rolling upland.
Having wheels or a wheel. Often used in combination: a three-wheeled bike.
To handle (a weapon or tool, for example) with skill and ease.
To exercise (authority or influence, for example) effectively. See Synonyms at handle.
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").