I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
cupola cupula cupulae cupel copula couple cupule copulae copal
cupola pol duopoly zeppoli spool splay replay papula maypole cupula copula hoopla byplay pula pool poly polo poll pole plea play pepla repoll spoil zeppole dipole whoopla
cup capo coup coupe cuppa cuppy scup