All three are types of aural imagery which is probably the most prominent type of imagery as it is easily identified by reading out the text. It is spread into many sections.
1. Assonance:
Assonance is a literary device in which vowel sounds are repeated within phrases or sentences that are close to each other in the text.
It can even occur within individual words. Assonance can involve the repetition of identical vowel sounds, or vowel sounds that are very similar.
When considering assonance examples, it's best to look at individual passages rather than the work as a whole. This is because the echoed vowel sounds must be in close proximity to one another. Consider a few brief examples from books, scripts, songs, and poems.
Example 1: "Hear the mellow wedding bells" - "The Bells" by Edgar Allen Poe
Example 2: "Hear the lark and harken to the barking of the dark fox gone to ground" - Grantchester Meadows by Pink Floyd
2. Sibilance:
Repetition of the 's' sound throughout a phrase or a sentence.
Sibilance is about the repetition of the "s" sound, not about the repetition of the letter S. This is important for two reasons. First, the letter C can also produce "s" sounds, as in the word "San Francisco."
Second, the letter S itself doesn't always produce an "s" sound. For instance, in the words "doesn't" and "always," the letter S makes a "z" sound that wouldn't be called sibilant.
Sibilance does not require that words with "s" sounds be placed directly next to each other in a sentence. Instead, sibilance occurs so long as "s" sounds are relatively close together within a sentence or paragraph.
Sibilance doesn't depend on where the "s" sounds occur within the words. They can be at the beginning, middle, or end of a word, and in stressed or unstressed syllables.
Example 3: From Edgar Allen Poe's "The Raven":
And the silken sad uncertain rustling of each purple curtain. (use of the "s," soft "c," and "ch" all together)
Example 4: From "Sea Fever" by John Mansfield:
I must go down to the seas again, to the lonely sea and the sky,
And all I ask is a tall ship and a star to steer her by. (repetition of the "s" sound)
3. Alliteration:
The repetition of the same consonant sound either at the beginning or into he middle of words.
Alliteration does not refer to the repetition of consonant letters that begin words, but rather the repetition of the consonant sound at the beginning of words. For example, the phrase “kids’ coats” is alliterative; though the words begin with different consonant letters, they produce the same consonant sounds.
Similarly, the phrase “phony people” is not alliterative; though both words begin with the same consonant, the initial consonant sounds are different.
In addition, for alliteration to be effective, alliterative words should flow in quick succession. If there are too many non-alliterative words in between, then the literary device is not purposeful.
Example 5: Paradise Lost by John Milton
John Milton makes masterful use of alliteration through the repeated use of "b," "f" and "a" in words like behemoth, biggest and born.
"Behemoth biggest born of earth upheaved
His vastness: Fleeced the flocks and bleating rose,
As plants: Ambiguous between sea and land
The river-horse, and scaly crocodile."
Example 6: The Soul selects her own Society (303) by Emily Dickinson
"The Soul selects her own Society" (303) by Emily Dickinson uses the "s" sound to create emotion and rhyme.
"The Soul selects her own Society-
Then - shuts the Door -"
All three types of aural imagery may help to create a slower or faster rhythm or may aid to convey a certain feeling such as excitement (usually done with letters such as 'r') or sadness (usually done with 's' sounds).
