The versification of My Last Duchess is marked by freedom of flow. The lines are arranged in rhyming couplets such as aa bb cc and so on. But these are not closed couplets that carry a complete thought or feeling. On the other hand, one line continues into the next line. This is thus an open couplet and the technique is called enjambment. This is more appropriate because the monologue form demands an unbroken flow of thought processes. It also caters to the digressions that are a necessary feature of thinking aloud. For example, if we look at the first two lines, we notice that while ‘wall’ and ‘call’ rhyme, the sense of ‘I call’ is only completed in the middle of the next line. The meter varies in different lines. But even so, the rhythm is calm and stately, much in keeping with the character of the speaker.
Another element that recurs in Browning’s poetry, as we have noticed, is alliteration. For example, ‘Oh sir, she smiled, no doubt. When’er I passed her; but who passed without much the same smile?‘ are not only musical but also stress the frequency of the offending smiles and the resultant irritation that they caused. The voice of the duke almost turns to a venomous tone that leads to his sinister commands. It is important to remember that the elements of poetic expression like rhyme, metre, alliteration are not an end in themselves. These elements have an artistic significance only in so far as they are an embodiment of the poet’s thought. Therefore, when we pick out a poetic device we must be able to say in which way it helps the poet’s thought, feeling and overall design.
Also, notice the diction in this poem. By using words such as ‘countenance’, ‘munificence’, ‘forsooth’ and ‘durst’, the poet has created an atmosphere of a bygone age, Renaissance Italy in this case. The duke speaks in an ironical tone whenever he refers to his last duchess…. she smiled, no doubt, Whene’er I passed her, but who passed without much the same smile?‘ His exclusive breeding and social status are evident in his reference to her death as “Then all smiles; stopped together‘. The speech is terse—not a single word can be removed without affecting the whole poem. There are sudden transitions, changes of mood and shifts in argument induced by the silent envoy. These not only help to generate an impression of realistic portrayal, but they also reveal the character not only of the duke but also of the duchess whom he wishes to denigrate.