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.
papula papulae papule papilla papal pepla papillae peepul papally pipal pupal pupil people popple peppily
pula cupula papula copula pul plea splay pule pepla puli papule hoopla cupule play byplay cupulae papulae pull peepul copulae replay cupola whoopla
pap papa papaw pappi pappy pawpaw