"This is just to say" analysis

i noticed that there was a "th" sound in the first stanza. "The plums that were in the icebox." I think this "th" sound makes it feels soft, the sentence is soft so that it shows he/she is apologizing. The last two stanzas have a similar structure, the second one has 2 5 2 3, and the third one has 3 5 2 3. And in the last stanza, the last two lines are parallel. So sweet and so cold. I think "so" emphasize how the plums taste like.

From this poem, it depicts a picture of somebody is stealing others food during midnight, and he wrote a letter to apologize.

There has a lot of "s" sound. It is a consonance. "This is just to say".