The words poling, polling sound the same but have different meanings and spellings. Why do poling, polling sound the same even though they are completely different words?
The answer is simple: poling, polling are homophones of the English language.
Present participle of pole.
The act of supporting or of propelling by means of a pole or poles.
The operation of dispersing wormcasts over the walks with poles.
One of the poles or planks used in upholding the side earth in excavating a tunnel, ditch, etc.
Present participle of poll.
the action of taking a poll
A technique that continually interrogates a peripheral device to see if it has data to transfer
Definitions 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").