Remember how you used to write those love letters to that cute girl (or guy) who sat across from you in fifth grade? (Don't worry, we won't tell.) It probably took you at least seventeen drafts before you got around to writing something that even remotely approximated what you felt about her (or him).
We're not saying that this poem is like your fifth-grade crush. And we're sure not saying that Auden writes like a fifth grader. (Then again, maybe you were a really talented fifth grader. Who are we to judge?) What we are saying is that this poem's variations in form convey the same mixture of urgency and hesitation that probably made you crumple up version after version of crappy love sonnets.
Auden is keenly aware that he's going to be writing for a massive audience, and that he's got a nearly impossible task in front of him. How do you chronicle the life of the most famous poet of your age? More important, how do you do so in a way that feels meaningful to you?
That tension is what gives this poem its sonic variants. Auden maintains a simple, restrained tone throughout the first section, laying out what we are able to tell about a man who died far, far away from our daily routines. It's akin to what you'd hear on the radio as you're brushing your teeth in the morning. A famous person died. We remember him.
But then the landscape shifts, and suddenly Auden is addressing Yeats directly, friend to friend. And that's where the language starts to get more impassioned and the metaphors begin to build.
And then, suddenly, as if the emotion was too much to handle, another form takes over. It's almost as if the personal address has become too emotional for our speaker, and so he reverts to tried-and-true forms like rhyme and elegy, in the lines "Earth, receive an honoured guest:/ William Yeats is laid to rest" (42-43).
The changes are lightning-fast; after all, the entire poem only takes up about seventy lines. And believe us, Auden packs a lot of emotion into those few stanzas. But then again, grief is temperamental and, well, hard to contain. Perhaps the chaos of this poem helps convey that sense of swimming without moorings that so often follows loss.