When you read "Piedra de sol" aloud, you might notice that you automatically swing into a cadence-like rhythm. There are no periods (even though there are some question marks in there) and most of the poem is made up of lists. This gives it a sort of a swinging feel.
You try: "a crystal willow, a poplar of water, / a tall fountain the wind arches over, / a tree deep-rooted yet dancing still." The fact that there are no verbs, just subjects, means you never arrive, so you never give your voice that downward direction that means "this is the end of the sentence." The effect is kind of hypnotic, because it goes on for a lot of lines. And even when it ends, it just circles back to the beginning and starts the whole process over again.
Another important technique used here is repetition: there are many words and phrases that get repeated several times within the same line or stanza, and this, too, gives the poem a you-are-getting-very-sleepy power that just might have something to do with its dreamy, deathly themes.
Check this out:
body of light filtered through an agate,
thighs of light, belly of light, the bays,
the solar rock, cloud-colored body,
color of a brisk and leaping day,
the hour sparkles and has a body,
the world is visible through your body,
transparent through your transparency. (25-33)
See what we mean? So much repetition makes the poem almost fold back onto itself. It makes you lose your orientation a bit and not know which way is backward and which way is forward. This puts you into a similar state of mind as the speaker, who can't tell past from present from future.
Sounds in Spanish
A lot of the editions of "Piedra de sol" are bilingual, so in the privacy of your own home (or, heck, on the bus if you want) give it a go and try reading the Spanish out loud. Even if you don't know what you're saying, try to feel the rhythm of the poem. Look back at "Form and Meter" for the rundown on the way the accents fall—the poem is written in a really regular meter where every other syllable is stressed. This gives it an almost song- or chant-like feeling, kind of like the hypnotic one you get in the translation. And that should help you pronounce those Spanish lines the way they were made to be said.