The words ball, bawl sound the same but have different meanings and spellings. Why do ball, bawl sound the same even though they are completely different words?
The answer is simple: ball, bawl are homophones of the English language.
Vulgar Slang The testicles.
To form into a ball.
A spherical object or entity: a steel ball.
A spherical or almost spherical body: a ball of flame.
To cry or sob loudly; wail.
To cry out loudly and vehemently; shout.
To utter in a loud, vehement voice. See Synonyms at shout.
A loud, bellowing cry; a wail.
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").