The words much, mutch sound the same but have different meanings and spellings. Why do much, mutch sound the same even though they are completely different words?
The answer is simple: much, mutch are homophones of the English language.
Great in quantity, degree, or extent: not much rain; much affection.
A large quantity or amount: Much has been written.
Something great or remarkable: The campus wasn't much to look at.
To a great degree or extent: much smarter.
The close linen or muslin cap of an old woman.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from the GNU version of the Collaborative International Dictionary of English 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").