The words all, awl sound the same but have different meanings and spellings. Why do all, awl sound the same even though they are completely different words?
The answer is simple: all, awl are homophones of the English language.
Every: got into all manner of trouble.
Being or representing the entire or total number, amount, or quantity: All the windows are open. Deal all the cards. See Synonyms at whole.
Constituting, being, or representing the total extent or the whole: all Christendom.
Being the utmost possible of: argued the case in all seriousness.
A pointed tool for making holes, as in wood or leather.
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").