Formation of Comparative Adjectives

There are two ways to make or to "form" a comparative adjective:

Short adjectives: add -er examples
1-syllable adjectives old, fast
2-syllable adjectives ending in -y happy, easy
RULE: add "-er" old → older
Variation: if the adjective ends in -e, just add -r late → later
Variation: if the adjective ends in consonant, vowel, consonant, double the last consonant big → bigger
Variation: if the adjective ends in -y, change the y to i happy → happier
Long adjectives: use more examples
2-syllable adjectives not ending in -y modern, pleasant
all adjectives of 3 or more syllables expensive, intellectual
RULE: use "more" modern → more modern
expensive → more expensive
With some 2-syllable adjectives, we can use "-er" OR "more":

quiet → quieter/more quiet
clever → cleverer/more clever
narrow → narrower/more narrow
simple → simpler/more simple
Exception: The following adjectives have irregular forms:

good → better
well (healthy) → better
bad → worse
far → farther/further