What literary device best enhances the rhythm of a poem by repeating initial words?

The literary device that enhances the rhythm of a poem by repeating initial words is known as anaphora. This technique involves the deliberate repetition of the first part of the sentence or a series of lines, creating a sense of rhythm and emphasis within the poem. It engages the reader, reinforces important themes or ideas, and can evoke strong emotional responses.

In poetry, this repetition not only enhances the musical quality of the language but also helps to structure the poem and draw attention to specific concepts or feelings. For instance, starting several consecutive lines with the same phrase can create a powerful, incantatory effect, making the message more memorable.

The other choices, such as contraction, couplet, and dénouement, do not serve the same purpose as anaphora. A contraction shortens words, a couplet refers to a pair of lines typically rhymed together, and dénouement describes the resolution of a plot in a narrative rather than an effect on rhythm or structure in poetry. Thus, anaphora stands out as the most effective device for enhancing rhythmic quality through the repetition of initial words in a poem.