Alliteration is the repetition of initial consonant sounds at the beginning of words. It is a sound device authors use to add pep to their work. You probably will recognize it best if I describe it as a tongue twister, like “Peter Piper picked a peck of pickled peppers” or “she sells sea shells by the sea shore.” Authors use it when they want to make their words stand out with a musical and somewhat whimsical quality.
Here is an example from one of Edgar Allen Poe’s famous poems, “The Raven.”
Once upon a midnight dreary, while I pondered, weak and weary,
Over many a quaint and curious volume of forgotten lore—
While I nodded, nearly napping, suddenly there came a tapping,
As of some one gently rapping, rapping at my chamber door. (Stanza 1)
Although this is not as obvious as the tongue twister, you can see how adding the repeated sounds makes the poem have a kind of hypnotic quality, kind of luring you in. In almost every case alliteration is made by using the same letter, although the “cah” sound in line two is made with different letter combinations. The effect is the same. The poem has a sing-song quality.
Alliteration can also speed a poem up, instead of slowing it down. Here is a famous example of alliteration from “The Charge of the Light Brigade.”
Theirs not to make reply,
Theirs not to reason why,
Theirs but to do and die:
Into the valley of Death
Rode the six hundred. (Stanza 2)
This alliterative example, “do and die” is especially powerful because it means that the soldiers have no choice but to follow orders, even if it means their death. The use of alliteration makes the phrase more meaningful, because it stands out and becomes charged with emotion.
Authors and poets use alliteration to make their words stand out, and to bring more meaning to their work. Sometimes the alliteration may not even be intentional, but it usually is. It is designed to make the words sing, and have a greater emotional impact. It can speed the work up, or slow it down, depending on how much alliteration there is and if there are other techniques used as well, such as rhyme.