In Langston Hughes's poem "I Dream a World," the repetition of the word "dream" emphasizes

Hughes opens and closes the lines with this word. He uses it for times and each of them has its own interpration. Hughes begins his poem with this line:

I dream a world where a man

The line means that the poem itself is about a dream, some unimaginative reality. After three lines he emphasizes the word again:

I dream world where all

With this line, Hughes introduces second set of his dream for the active process. The process is about the present that Hughes has not yet given up that he uses present tense. Therefore, the next line starts the next concept:

A world I dream where black or white

And the last line completes the process by summing up all the wishes:

Of such I dream, my world.

The word "dream" emphasises the longing which the persona holds that is not quite tangible - the repetition implies this "dream" is reoccurring, showing that the persona's longing is all the more strong.