The words pearl, purl sound the same but have different meanings and spellings. Why do pearl, purl sound the same even though they are completely different words?
The answer is simple: pearl, purl are homophones of the English language.
Variant of purl2.
A smooth, lustrous, variously colored deposit, chiefly calcium carbonate, formed around a grain of sand or other foreign matter in the shells of certain mollusks and valued as a gem.
One that is highly regarded for its beauty or value.
To flow or ripple with a murmuring sound.
The sound made by rippling water.
To knit (yarn) with a purl stitch.
To edge or finish (a handkerchief, for example) with lace or embroidery.
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.