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.
summa summae sum sumo soma sima samba sim som same seam seem seme semi smew some cyma
gumma summa umm pneuma chummy douma mummy tummy duma summae rumba mammae rummy puma mumm mamma momma dummy gemmae louma gemma lemma gummy gamma comma luma yummy