Tennyson wrote this poem based on an episode of The Odyssey where Odysseus and his men stay on an island where the people who live there are subject to a strange and powerful plant that reduces those who consume it to an almost drugged state of bliss and happiness with no desire to leave or to venture away. As a result, the poem tries to capture this feeling of languid stasis in both its rhythm and its diction. Consider, for example, the following quote:

Most weary seem'd the sea, weary the oar,
Weary the wandering fields of barren foam.
Then some one said, "We will return no more;"
And all at once they sang, "Our island home
Is far beyond the wave; we will no longer roam."

Note the repetition of the word "Weary" in this quote and the way that the diction in phrases such as "wandering fields of barren foam" is used to describe the negative way in which the islanders feel about leaving this island and venturing forth onto the sea. In addition, the final rhyme with "home" and "roam" helps introduce a hypnotic, sing-song tone, which enacts the way in which the lotos plant manages to entrance those who succumb to it.