Dinah writes: "I look forward to hearing more from you about prayers and poems -- especially how verse form affects the use and meaning of prayers, and about the inner poetic structure of the Psalms."
Gosh, I don't know much about either of these, Dinah.
The closest I can come on the former ("how verse form...") is to say that when I was a boy, the Mourner's Kaddish had such complete authority of sound that I didn't care what it meant, phrase by phrase. I knew the general sense from the English version on the facing page, and that was enough to tether my flight. This became the model for how I read Cummings, then "Prufrock," then Pablo Neruda's Versos del Capitan and the Residencia poems, my first loves in the art.
For me it's not the verse form that's significant in connecting poetry & prayer, but the imaginative projection that one does in reading verse. Take the poem, I tell my students, as a script for you to say; the same holds true for the siddur. This is why I sometimes flinch at my rabbi's suggestion that we ignore the words of, say, the Amidah & "pray what's in our hearts." The script can be used to unlock things "in our hearts" that we didn't know were there--associations, emphases, sudden insights--and as a means of self-transformation. Pouring out the heart can do the same, but it also can stay entirely superficial, just as rote as any fixed prayer-form. Especially when everyone's watching their minyan-mate from the corner of their eye, trying not to be the last one standing:
Shacharit is going fastAs the boys of Green Day sing, or would.
But that guy wants to make it last
Wake me up
When the Amidah ends...
(I'd like that even more as a Yom Kippur parody. "Wake Me Up When Neilah Ends.")
--Time to wake the kids. More anon.