For all its depressing, old age reflection, "The Wild Swans at Coole" does manage to pack in some fun sounds. After all, it's not like this poem fails to recognize beauty and vitality. In a paradoxical way, the speaker can only reflect on his lack of energy because he appreciates it so much in the swans before him. By that same token, this poem offers up its own form of ear candy to appreciate. Tellingly, this comes in a stanza where the speaker is most fervently admiring the swans and their beauty.
So, we cover the nice, symmetrical form accomplished by the rhyme scheme over in our "Form and Meter" section. For all your rhyming needs just click on over there. What we'd like to focus on here is the poem's use of alliteration, particularly in stanza 4. It's in this stanza that the speaker is admiring the swans, whose "hearts have not grown old" (22). They are beings of "Passion or conquest" (23), and we think this kind of enthusiasm for the swans' energy explains phrases like "cold / Companionable streams or climb the air" (20-21) and "wander where they will" (23). In both cases, we notice the repeated beginning consonant sounds of the words, which lend a kind of energy and, well, playfulness to the poem's sound. The repeated hard C sounds of "cold," "Companionable," and "climb" are followed closely by the W's in "wander," "where," and "will." It's as if, with these sonic bursts of repeated sound, the poem itself can't help but reflect the energy and vitality of the swans it admires. These alliterations burst from our mouths like so many birds, busting forth into the blue beyond!