An ELT Glossary : Assonance, Alliteration and Consonance

Assonance, alliteration and consonance are all rhetorical devices, found primarily in literary writing, but also in other genres such as advertisements and promotional text, political speeches and other persuasive text. Here are their definitions and some examples:

Alliteration is the repetition of the same consonant at the beginning of a number of words in close succession. Some examples:

a) The repetition of /b/ in Tolkien's novel "The Return of the KIng" describing how Theoden took a horn: "...from Guthláf, his banner-bearer, and he blew such a blast upon it that it burst asunder. "

b) The repetition of /h/ in Yeats poem "The Lake Isle of Innisfree" : Nine rows will I have there, a hive for the honeybee

c) In song lyrics : "Whisper words of wisdom" (The Beatles - Let it Be); 

c) In political speeches : eg Barack Obama describing the work of the US military in distant, different, and difficult places.” or Martin Luther King : "...the dark and desolate valley of segregation.".

d) In advertising slogans : Don't dream it. Drive it (Jaguar); You'll never put  a better bit of butter on your knife (Country Life) Interestingly, many people seem to remember this last example as finishing on your bread - thus continuing the alliteration.

e) The use of alliteration in brand names, character names, novel and film titles : Coca-Cola; Dunkin' Donuts; Range Rover; PayPal; Ted Talks; Mickey Mouse; Pride and Predjudice; Dirty Dancing.

Consonance is the same except that it describes instances where the consonant sound is described not just at the beginning of the word, but either at the end (in some definitions) or (in others)  anywhere. A few examples using the broader definition include : 

a) Poetry : /s/ in celebrate myself, and sing myself (Walt Whitman)
b) Advertising slogans : America runs on Dunkin' (Dunkin' Donuts)
c) Titles : Sense and Sensibility
d) Song lyrics : They paved paradise and put up a parking lot (Joni Mitchell- Big Yellow Taxi)

Assonance is similar except that it is the vowel sounds rather than the consonants which are repeated.  Again, just a few examples : 

a) Poetry : /i:/ in  Beside the lake, beneath the trees (Wordsworth)
b) Advertisements : The best a man can get (Gillette)
c) Political speeches : /ɪ/ in  We will build the roads and bridges, the electric grids and digital lines…(Barack Obama)

Often of course, more than one of these devices may be combined. Notice how the following example of a song lyric shows all three : alliteration /k/, consonance /s/ and /t/ and assonance /e/:  
I must confess that in my quest I felt depressed and restless(Thin Lizzy, "With Love")

while the Obama extract immediately above shows not only assonance but also consonance of the /d/ sounds.