Final answer:
The repetition in the poem's lines builds suspense, emphasizes the narrator's fixation, and contributes to the Gothic atmosphere by using sound effects and rhythm to evoke dread.
Step-by-step explanation:
The effect of the repetition in the lines from the poem is to create a sense of intensity and fixation. The narrator's repeated mention of the phrase 'some visitor entreating entrance at my chamber door' paired with the initial sounds of a mysterious tapping serve to build tension and a haunting atmosphere. The narrator's insistence on dismissing the source of the sounds as merely 'this it is, and nothing more,' highlights their attempt to rationalize their fear. Repetition plays a role in emphasizing a growing obsession and the declining mental state of the speaker, capturing the reader's attention and echoing the repetitive nature of the tapping that disturbs the silence. This technique is characteristic of the Gothic style found in the works of Edgar Allan Poe, which often features the use of sound effects and rhythm to build suspense and contribute to thematic elements of dread and the supernatural.