Final answer:
The speaker's tone about the land of nod is initially pleasant and dreamlike, but becomes darker and more ominous as the poem progresses.
Step-by-step explanation:
The speaker's tone about the land of nod is initially pleasant and dreamlike, with images of castles in the clouds and a summer sky. However, as the poem progresses, the tone becomes darker and more ominous, with references to frozen images, dead faces, and a borderless nation of snow. Overall, the speaker's tone evokes a sense of melancholy and a contrast between dream and reality.