"Nothing Gold Can Stay" packs a lot of alliteration into its 8 lines. This alliteration combines with the poem'a steady meter and rhyming couplets to give it a very musical sound; the poem is easy to memorize and satisfying to read aloud. This musicality, in turn, adds to the poem's sense of having an important message that should be passed on to others.
Alliteration also connects certain words in the poem. For example, in line 1 the hard /g/ sound shared be "green" and "gold" connects the two words on the level of sound, supporting their metaphorical connection within the line.
Line 2 then contains the most alliteration per line, with four repeated /h/ sounds:
Her hardest hue to hold.
The /h/ sound requires an exhalation of breath, making the line feel like a sigh—perhaps reflecting a sense of resignation at the fact that this golden hue simply cannot last. The reader's breath also almost runs out by the end of the line, reflecting the idea of time being up.
In line 6, the sibilance of "So" and "sank" evokes the air being let out of a balloon, reflecting the feeling of Paradise sinking into the earth. Sibilance is also evocative of a hissing snake—which, of course, was the creature who tempted Eve and spurred the Fall of Man in the Bible.
The alliterative letters within the lines move from /g/ to /h/, to /l/, to /s/, and lastly to /d/. This movement from sound to sound emphasizes the fact that nothing can stay. This alliterative progression also very subtly forces the tongue to move in the mouth from high to low. The /g/ and /h/ sounds require a higher tongue position than the more guttural /l/ and weighty /d/ sounds. This emphasizes the idea of falling as the poem moves from higher, airy sounds to darker ones. This underlines the message of the poem, that everything which is at one time light and youthful must sink into dullness.