The words cause, caws sound the same but have different meanings and spellings. Why do cause, caws sound the same even though they are completely different words?
The answer is simple: cause, caws are homophones of the English language.
The producer of an effect, result, or consequence.
The one, such as a person, event, or condition, that is responsible for an action or result.
A basis for an action or response; a reason: The doctor's report gave no cause for alarm.
A goal or principle served with dedication and zeal: "the cause of freedom versus tyranny” ( Hannah Arendt).
Plural form of caw.
Third-person singular simple present indicative form of caw.
Definitions from The American Heritage® Dictionary of the English Language, 4th Edition, from Wiktionary, Creative Commons Attribution/Share-Alike License 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").