As is the case for most of the aspects of figurative language discussed thus far in the series, figurative language most often works on the level of meaning, comparative and overlapping layers of meaning especially. Simile and metaphor are the leading examples, where aspects of a given entity are highlighted through juxtaposition with another, generally dissimilar one. However, figurative language can operate on many other levels as well, and the level of sound is the area where alliteration makes its presence felt.
Although our literary experiences today are almost entirely text based, in that we read works rather than listening to someone read them aloud, the place of "sound effects" in good writing is still easily recognized. Rhyme is perhaps the best and most well known example of sound effects in literary writing, but alliteration is a close second, and for centuries in the oldest forms of English it was the dominant ordering sound effect in all verse. Alliteration most simply defined is the occurrence of the same sound at the beginning of at least two words that are presented near each other in a given text. Note that the lead sound is the vital consideration, not the lead letter. In English where the same letter can often make two or more different sounds, this is a point not to be forgotten. "City" and "cake" do not alliterate despite beginning with the same letter, nor do "knight" and "kite" (even though this last pair happens to rhyme). On the contrary, "cake" and "kite" do alliterate despite the differing lead letters, as do "city" and "sorry."
Many tongue twisters are exaggerated examples of alliteration, where every or nearly every word in a given line or verse begins with the same sound.
"She sells sea shells down by the sea shore"
obviously uses the letter s to begin words almost to the point of absurdity. In this case, the effect of the device is to make the whole sequence challenging to pronounce by using a dominant beginning sound but altering the sounds around it slightly to trick the reader into repeating not only the lead s sound, but also other parts of the previous words where they are no longer applicable.
This trick shows the ability alliteration has to affect the reading process by drawing together nearby words so that they remain in our minds for longer, and so that each reminds us of the other. For example, in the line:
"The whispering winds swirled the mists of memory, wandering over the moors,"
we immediately get a sense of the place merely from the sound of the line. "Whispering winds" uses the repeated w sound to give us a hushed feeling which is reinforced by the resemblance of the sound to the actual sound of wind. The w sounds are wispy and airy, which perfectly mirrors the things being described. Next we see another alliterated pair, "mists of memory," which are joined by the common m sound which is deeper and fuller, appropriately describing darker, equally ephemeral but more serious ideas. Finally, we see "wandering" and "moors" in the last part of the line, uniting it to the two previous parts through the use first of a w sound followed closely by an m sound. This unites the two previous alliterated aspects of the line, bringing them once more to mind and encouraging us to hear their echoes of both sound and meaning in the final words. Although alliteration operates on the level of sound, the repetition with variation encourages us to consider how the words are different as well, how their meanings can be compared, and how they are related to each other. Alliteration is used in jingles to make them easier to remember, songs to make them sound better (because the ear loves repeated sounds in moderation), and especially in poetry for both its pleasing qualities, and for its ability to draw together disparate meanings.