Repetition in poetry as a literary device goes far beyond mere parroting of words. It gives drive to poetry, as it does for any song from primitive chant to hard rock; it is a unifying device that adds commentary to a poem's narrative; it solidifies and often alters meaning. It thereby adds change, development and meaning to a poem's theme.

Repetition Alters Theme

The theme of the anonymous poem "Tom a' Bedlam" alters significantly as the work's refrain repeats. Tom, a beggar from Bedlam asylum, calls for "any food, any feeding" and says "be not afraid, poor Tom will injure nothing." Stanza after stanza, Tom's ravings get more maniacal -- "I know more than Apollo" -- and apocalyptic -- "with a burning spear and a horse of air to the wilderness I wander." With each refrain, Tom is more terrifyingly sane and otherworldly. The theme moves from pity for disability to the questioning of one's own sanity.

Repetition Extends Theme

The ballad "Lord Randal" reinforces its theme of love gone sour as the lord's mother questions him incessantly about his hunting and his dinner with his lover. "I am sick wi' hunting and fain would lie down," says the Lord at each stanza, eventually changing to "I am sick at the heart"; it becomes clear that he is poisoned by his loved one -- for hunting new women, perhaps -- and is on his last legs. Love is sour from the poem's beginning; love and death are natural companions by the end.

Repetition Deepens Theme

Repetition is not always in stanzas; parallelism is a highly effective poetic device for deepening thematic meanings. Walt Whitman's "I Hear America Singing" repeats the word "singing" 10 times, each repetition associated with a craft, trade or working person. The national song both unifies, since all are Americans singing it, and diversifies, since many different workers join in. Whitman's theme of national solidarity is intensified to the point where the nation itself has a universal voice, made up of thousands of singers. The theme doubles its effect; the song is many, and one.

Repetition and Three Interpretations

Finally, a single repetition may deepen, extend and alter a theme. Robert Frost's "Stopping by Woods" evokes a theme of self-reflection as the horseman watches a winter's snowfall. However, he repeats "miles to go before I sleep" at poem's end. This may indicate a deeper need for peace, an extension of our connection to nature or even a longing for death. All these interpretations are possible; the repetition brings them to light.