It isn’t unusual for poets to cross over from other styles into plain speech resonance and back again.  Even the poetry of Dylan Thomas, whose example I often cite for its oratorical/pontifical qualities, has been known on rare occasions to yield a plain-speech resonance element.  In fact, if you listen to him read his prose fiction, you’ll note there is much more of plain-speech resonant quality to it.  The closer he gets to his Welsh roots and away from his English heritage, the plainer he gets.

In his poetry, the two poems I classify as plain speech more than any others are “In My Craft or Sullen Art” and “Do not Go Gentle into that Good Night” (the latter of which he wrote while his father was dying.)  Part of this plain-speech quality, but only PART, is influenced by the delivery.

And then, just to re-calibrate, I’ve also linked “A Refusal to Mourn,” which is distinctly out of the plain speech resonant category.