This poem is a dramatic monologue because the only speaker in the poem is Alfonso. Browning uses Iambic Pentameter as the metre to create a sense of natural speech; this makes the poem avoid sounding like a pre-meditated speech. Another reason why the poem sounds like natural speech is because the poem is written in rhyming couplets. The metre and rhyme scheme create a distinct poetic voice is make the poem and speaker sound to the reader like
he is speaking naturally.
The poet gives the speaker a strong undertone of malevolence and cruelty. “I gave commands… Then all smiles stopped together.” This makes it unclear to the reader on whether the “command” was him telling his last duchess to stop smiling or telling someone to kill his duchess, which is maybe why “All the smiles stopped together.” This ambiguity creates a distinct sense of the speaker being more malevolent and slightly creepy than an obvious threat to the Count and the reader.
The speaker tells his guest to admire the portrait of his last duchess but this make s you unsure on whether the speaker wants his guest to admire his wife or the fact that it’s a beautiful piece of art, “That piece of wonder… Will’t please you sit and look at her… Fra Pandolph’s hands worked busily a day,” At the start of the poem there he seems to miss his duchess, which is why he adores admiring the painting of her but on the other side he may just be proud that he owns beautiful piece of art painted by the “famous” Fra Pandolf.