Assonance

Alliteration is all the same consonants:

Round the rugged rock the ragged rascal ran.

Assonance is all the same vowels:

Blue moon you saw me standing alone.

Deep heat for tired feet.

We have two problems here with assonance.

The first is that, despite Animal Farm and the Pigs, not all vowels are equal. Blue moon has two long vowels. Eat meat has long vowels. But usually we use short vowels. 

(It reads like this: bt usly we us(e) shrt vowls: try it for yourself.)

But repeating lots of short vowels isn't much use really.

Standard Arabic is much easier here: it simply leaves out all the short vowels and just includes the long ones. We don't do that, we sort of put the short vowels in, which makes our spelling almost impossible. Assonance too.

Then there are the different vowel sounds in the English speaking world. This comes from Singapore where Singlish is all the rage:

They are different in Scotland, in the North of England, in Wales and in London too. And they are different in Australia, Canada and the West Indies. Indians, too, have different ways of saying English vowels.

So assonance is very hard to get right

.

For those who study the English classics, too, it is very hard to understand assonance because of the Great Vowel Shift.

Of course, if you combine assonance and alliteration, you get a pun.

Shakespeare did some very clever puns. But they don't work today. I seem to remember a lot of clever stuff punning dollar and douleur...

Here is a good example or assonance being used as a pun:

"From forth the fatal loins of these two foes,
A pair of star-crossed lovers take their life."

The word ‘loins’ would originally have been pronounced the same as ‘lines’.

This pun refers to the fatal blood lines of Romeo and Juliet – the families that they descended from are the reason for their death, as well as their ‘loins’ (their physical relationship). 

When assonance works without alliteration, though, the result is very pleasant:

I met a traveller from an antique land. (Five short “a”). Ozimandias by Wordsworth.

Rage against the dying of the light. (two long “i"s). Dylan Thomas.

Proverbs and catch phrases are good at assonance so they can be easily remembered:

High as a kite.
Happy as Larry.
How now brown cow.
A stitch in time saves nine.

Cats have nine lives.
Many hands make light work.
Rain, rain, go away, comae again another day.

And advertisers know this too:

Company names:

sweetgreen
Patagonia
Asda

Rhyme flows from assonance easily and it is easily remembered

An apple a day keeps the doctor away.
A Mars a Day helps you work rest and play.

Play it again Sam!