When you read a sonnet, the rhythm is gonna get you. By that, we mean that the use of iambic pentameter will lull you into an expected pace of language as a reader. Our man Big Willy knows this, and so he both propels us along with his lines of iambic pentameter, and keeps us on our toes in this poem with an occasional trochee or feminine ending (for more on those techniques, check out "Form and Meter," won't you?).
Naturally, then, the rhythm of the lines is going to produce a particular kind of inertia when you read this (and that becomes really obvious when you read this out loud), but we're not here to talk to you about the beat, folks. Nope, we want to focus more on the melody, the sounds that Shakespeare strings together in such succulent, succinct, super-special series.
In case you didn't realize, that was a clue. To what, you ask? To alliteration. This sonnet has a ton of it. It's almost like Big Bill couldn't help himself. If you follow us, though, we think that some of his alliterative choices are on purpose, and for a very good reason.
Let's take lines 2 and 3 for example:
Or as sweet seasoned show'rs are to the ground;
And for the peace of you I hold such strife,
Read them out loud. Yes, right now! Notice anything? You should have detected a sound like steam escaping a kettle. That's all those S sounds here: "sweet seasoned show'rs," "peace," "such strife." S is a smooth sound. It comes easily out of the mouth, almost like a sigh. So, it makes sense that Shakespeare's speaker puts a lot of those sounds into these lines that describe his affection for the "you" of the poem. Even when he's describing how tormented he is by this love, those S sounds are still used ("such strife"). It's as if he can't escape this love, even (or especially) when he's tormented by it.
Dig it? Good, because there's more. For example, check out lines 7 and 8:
Now counting best to be with you alone,
Then bettered that the world may see my pleasure;
Reading these lines aloud will again reveal some alliteration here. These lines sound bouncy, don't they buddies? That's because of the brilliant, bombastic B sounds. Read these lines again, paying attention to your lips as you do. They should be pursed to make all those B sounds: "best to be," "Then bettered." Fun, right? The Shake-anator adds alliterative energy to these lines to emphasize the speaker's underlying joy at being with the "you" of the poem (the only trouble is that the speaker doesn't know how exactly he should spend that happy time).
Finally, we have more alliteration in lines 9 and 11:
Sometime all full with feasting on your sight,[…]
Possessing or pursuing no delight
Here, the sounds (F sounds in line 9, P sounds in line 11) are more explosive and less enjoyable. (Let's face it: you can get a pretty negative reaction by just making the F sound, or the P sound at somebody. No words required!) Again, though, Shakespeare's alliterative choices are in line with the speaker's mood. Towards the end of the poem, he's so torn about how best to approach his love for the addressed that these frustrated sound-pairs start to emerge. Even at the sonic level, we can feel his pain—his powerful, palpable, prolonged, and pernicious pain.