Firstly, because the sonnet is a very strict form, the author has to be very careful in constructing his poem, to ensure that it fits the design constraints. One of these constraints is that the sonnet is very short, with only 14 lines. This forces the author to distill his thoughts and feelings into as compact a form as possible.
This distillation process means that the waffle that would have filled up a piece of prose has to be cut, and leaves a much clearer, less cluttered version of his feelings. Often, he has to sum up in one line of the poem what he would normally have written a paragraph or more on.
For example, “Shake hands forever, cancel all our vows” sums up very concisely the idea of the break being forever, with no possibility of reconciliation, whilst also adding to the ease of understanding and therefore also to the meaning of the poem.
Another constraint of the sonnet is the length of the lines themselves. In a sonnet, the rhythm is always iambic pentameter, which means that there must always be ten syllables per line, with each second syllable being stressed. Where the author breaks this pattern, it must obviously be for a good reason, when the author wants a certain word or syllable to be stressed.
This in itself will naturally add to the meaning of the poem. This, in addition, to the constraints of the number of lines, again causes the poem to have to be compressed, clarifying the poem’s meaning, and thereby enhance it. For example, in the first line, there should be no stress on the third syllable, but the author has written the poem so that there is, stressing the “no” and giving weight to the definitiveness of the first two quatrains.
The author again breaks the rhythm in the last two lines, using eleven syllables instead of ten. This is clearly not a mistake or an accident, and has been done for one of two reasons; to add emphasis to these lines because seem out of place due to their length, or because the author felt that he simply could not sum up his feelings in the eleven syllables that the standard sonnet affords him.
When looking at the rhythm, we should look not only at the line length but also at the rhyme scheme. In the first two quatrains, the rhyme words are very harsh, distancing the author from the poem. For example, there are very harsh consonant sounds of “part” and “heart”, However, in the third quatrain, there are much softer sounds, such as “breath”, “death”, “lies” and “eyes”. The harsh ‘r’s and ‘t’s are replaced by softer ‘th’s and ‘s’s.
Indeed, this pattern is mirrored throughout the poem; in the first two quatrains, the language is harsh, and cold, and after the volta, in the third and fourth quatrains, the language is softer and more personal. Again, this is a function of the form of the sonnet; there must be a drastic change of ideas after line eight. For example, there is the brutally aggressive “you get no more of me” in the second line, and the much gentler “Now at the last gasp of love’s latest breath”.
However, the author uses the volta not only to change the language but also the entire message. Instead of driving her away from him as he did in the first eight lines, he is now reminding her of how serious the loss of the relationship will be. He goes from commanding to almost begging.
The orders in the first two quatrains such as “be it not seen” are replaced with conditionals, such as “if thou would’st”; it seems almost as though he is pleading with her. Also worth noting is the way in which he goes from using the aggressive “you” to the gentler “thou” after the volta. This clearly adds to the message of the poem.
However, despite the change from the aggression of the first half of the poem, there remains a slight hint in the second half, as the author threatens his lover, telling her that if she leaves him, then she will be a murderess, having killed not just their love, but love itself.
It is clear that the form of the sonnet has greatly added to the meaning of the poem. In refining the poem to fit the constraints, the author has clarified the message and deepened the meaning of what he is trying to say. Furthermore, where the author for some reason breaks the rules of the poem, this adds yet more to the meaning of the poem, emphasizing certain parts and making other parts stand out.