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.
silken slacken sleeken slicken silicon silicone slogan
silken liken alkene blacken calkin malkin slacken sleeken slicken welkin
silkie silk silky selkie silica siliqua siliquae silique slake sulk sulky