Comparatives and superlatives have very similar rules, and these depend on the number of syllables of the adjective. There are some cases in which more than one form is acceptable. Let's see these rules.
CVC case
If the adjective ends in "consonant + vowel + consonant", double the consonant and add -er
big - bigger
fat - fatter
thin - thinner
All others
Add -er
old - older
short - shorter
Remove the -y and add +ier
happy - happier
friendly - friendlier
If the adjective has more than 1 sylllable use "more" + adjective.
handsome - more handsome
interesting - more interesting
We normally use the word "than" when making a comparison. For example:
My sweater is bigger than yours.
Our new teacher is more relaxed than the precious one.
CVC case
If the adjective ends in "consonant + vowel + consonant", double the consonant and add -est
big - the biggest
fat - the fattest
thin - the thinnest
All others
Add -est
old - the oldest
short - the shortest
Remove the -y and add +iest
happy - the happiest
friendly - the friendliest
If the adjective has more than 1 sylllable use "the most" + adjective.
handsome - more handsome
interesting - more interesting
Superlatives are preceeded by the article "the" in most cases,
This is the most interesting painting of the gallery.
There are a few adjectives that will have different comparative and supperlative forms:
good - better - the best
bad - worse - the worst
far - farther - the farthest (more literal meaning)
far - farther - the farthest (more figurative meaning)
We can find some adjectives that can follow more than one rule. For example:
Some nouns can be countable or uncountable depending on the context, or the meaning that we want to express. We have one example below. Can you guess which one is countable and which one is uncountable?
I like pineapple on my pizza.
Uncountable. The pineapple is an ingredient of the pizza, and we don't really count individual units. This example is similar to "sand" or "sugar".
I have some pineapples on my fridge.
Countable. We can literally take the individual units and count them.
Chocolate (liquid) Uncountable
Chocolates (units) Countable
Paper (material) Uncountable
Paper (essay or piece of written work) Countable
Iron (material) Uncountable
Iron (device) Countable
Sometimes we can transform an uncountable noun into a countable one, specially if it is clear that we are referring to a specific unit. For example:
I want two beers, please.
I want a coffee, please.
She bought three sodas.