I've been thinking a lot about rhyme lately, as I mentioned in my
writeup in the
Things that rhyme with orange node. While the
E2 poetry crowd seems to lean very heavily toward
free verse, rhyme is not a topic that is given much
consideration, except in such
silly nodes as the orange one.
First, let's start by considering the definition of "rhyme." My dictionary (as a secondary definition) says "A word agreeing with another in terminal sound." This is the kind of rhyme we all learned in grammar school, but in fact the primary definition of rhyme is much broader: "Identity in sound of some part." Interestingly, the etymology of the word "rhyme" sees an evolution from an Old High German word meaning "to put in a row," which seems to apply more to a poem's rhythm than what we consider its rhyme.
The broader definition encompasses both the concept of assonance (meaning two words having similar vowel sounds) and consonance (which means two words with similar consonants). Consider the pair claim/plain--they do not completely agree in terminal sound (ending as they do in different consonants), but they do share the central vowel construct which allows them, to our ears, to rhyme. I would argue (as would many poets, I believe) that the pair dawn/down rhymes--in fact, in this case only the vowel changes, something which draws attention to the pair and which I feel adds remarkable emphasis.
The question of whether rhyme--in the strict sense of the first definition above--should be part of English poetry has been hotly debated through the years, especially during the Renaissance, when a resurgence of interest in unrhymed Greek and Latin poetry raised the question anew. To see how this has been illustrated through the years, consider the poems If by Dull Rhymes our English must be Chain'd by John Keats or the tongue-in-cheek A Fit of Rhyme Against Rhyme by Ben Jonson. But an argument against rhyme can be made on a different, and I feel more compelling basis: first, that the English language, as syncretic as it is, is poor in rhyme, and finding appropriate rhymes can be a challenge; second, rhyme is simply an alien concept I think was foisted on the language after the Norman Conquest--before then, ALL English verse was based on the kind of alliterative forms found in, for example, Beowulf.
So what are we left with? Do we abandon rhyme altogether as being simply too difficult for practical use? I don't think so. I think talented writers can continue to use the strict definition as a challenge to produce great rhyming works that do not unnecessarily bend the language. I do feel that greater use should be made of consonance and alliteration as tools to expand the poet's repertoire of rhyme, as long as they are used in a balanced and sensible way. For my part, I would also like to see more poets move away from the unconstrained format of free verse to pursue either loosely rhymed forms or "The Mighty Line offered by blank verse. I tend to believe that we produce our most creative material when working under some level of constraint, but that's a completely different writeup altogether.