The words been, bin, bine sound the same but have different meanings and spellings. Why do been, bin, bine sound the same even though they are completely different words?
The answer is simple: been, bin, bine are homophones of the English language.
Past participle of be.
A container or enclosed space for storage.
To place or store in a bin.
The flexible twining or climbing stem of certain plants, such as the hop, woodbine, or bindweed.
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.