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.
pirog prog pirogue piragua piroque prig pargo park perk pork
pirog frog virga grog prog trog
pro pair pier prao proa prow pyro spiraea spire spirea spiry