Nicholson Baker on rhyme
From The Anthologist:
The tongue is a rhyming fool. It wants to rhyme because that's how it stores what it knows. It's got a detailed checklist of muscle moves for every consonant and vowel and diphthong and fricative and flap and plosive. Pull, relax, twitch, curl, touch. And somewhere in there, on some neural net in your underconsciousness, stored away, all these checklists, or neuromuscular profiles, or call them sound curves, are stored away, like the parts of car bodies, or spoons, with similar shapes nestled near each other. Broom and loom and tomb and spume and womb and whom are all lying there on the table in one spot. And you figured all that out by yourself. They rhyme.
So what rhyming poems do is they take all these nearby sound curves and remind you that they first existed that way in your brain. Before they meant something specific, they had a shape and a way of being said. And now, yes, gloom and broom are floating fifty miles away from each other in your mind because they refer to different notions, but they're cheek-by-jowl as far as your tongue is concerned. And that's what a poem does. Poems match sounds up the way you matched them when you were a tiny kid, using that detachable front phoneme. They're saying, That way that you first learned language, right at the beginning, by hearing what was similar and what was different, and figuring it all out all by yourself, that way is still important. You're going to hear it, and you're going to like it. It's going to pull you back to the beginning of speech.
Rhyme taught us to talk.