Alliteration is the repetition (usually and traditionally, of a consonant sound) found at the front of a group of words that are placed together. For example, "dive, down deep" is an example of alliteration: there is a "d" at the beginning of each word, and they have the SAME sound.
Alliteration is a poetic device. Poetry was originally intended to be read aloud. The use of literary devices like alliteration, assonance, consonance and onomatopoeia creates patterns of sound that are most effective when heard rather than read. Alliteration, as well as the other devices mentioned, give poems a musical quality.
Examples found in "Song of Slaves in the Desert," by John Greenleaf Whittier include the following which repeats the "w" sound in the first part of the phrase, and the "f" sound in the second part of the phrase. Remember, the SOUND must be the same:
...Wells of water, fields of food...
Repetition is used in a poem for emphasis. By using the same word or phrase repeatedly, the author is trying to drive a point home. There are several uses of repetition in Whittier's poem. Repetition can be used by repeating a word, a phrase or duplicate sentence structure. For example:
Here we thirst and here we hunger,
Here the Moor-man smites in anger...
In this example, "here" is repeated several times, but the phrasing is also repeated in the first line where the structure of each phrase is similar, as seen in "Here we..."
Similar repetition of phrases is also found in the following lines, which compare "we" to "thou" ("you"):
We are blind, but Thou hast eyes;
We are fools, but Thou art wise!
However, the question repeated that has the most impact is found in "Where are we going?" which starts in the first stanza
WHERE are we going? where are we going,
Where are we going, Rubee?...
Speak and tell us where we are going,
Where are we going, Rubee?
The variation is only in adding the name "Rubee" (which means "God"). The point of this repetition is that these people, enslaved and traveling across the desert, are thirsting, hungering and dying. As they walk, the most important element is not the memories describing what they have lost—what they were forced to leave behind—(which provides the reader with a stark "before/after" contrast), but the slaves' burning curiosity as to where their journey will take them. They wish for their "Atka" (freedom) and ask God to return them to their cherished homes.