Comparative Adjectives
Comparative adjectives are used to compare the qualities of two nouns, in the comparison one of the nouns will have a quality to a higher degree than the other. The comparative form of most adjectives is formed by adding -er to the base form of short adjectives (adjectives that have 1 or 2 syllables) i.e. (tall, taller, small, smaller, broad, broader, round, rounder, etc.), however there are exceptions. A syllable is a distinct vowel sound a word makes when it is pronounced. The word -than is frequently used to make comparisons however it is not always necessary.
Note: There are many short adjectives that use the word -more instead of ending in -er to form their comparative form, especially adjectives that end in the letter -e, these exceptions must be memorized.
Short adjectives - Formation Exceptions
If a one or two syllable adjective ends in the letter -e i.e. (safe, huge, fine, large, etc.) we simply add -r to them instead of -er i.e. (safer, huger, finer, larger, etc.)
If a one or two syllable adjective ends in a vowel + consonant i.e. (sad, big, wet, etc.) we double the consonant and add -er i.e. (sadder, bigger, wetter, etc.)
If a two syllable adjective ends in a consonant + y i.e. (noisy, lazy, happy, etc.) we remove the -y and add -ier i.e. (noisier, lazier, happier, etc.)
Short adjective examples
Ex: He is taller than his brother.
Ex: This street is wider than the one I live on.
Ex: Bigger engines use more fuel than smaller ones.
Ex: Do you feel better now?
Short adjectives that use the adverb -more
There exist short adjectives of 1 or 2 syllables that use the adverb -more to form their comparative form instead of adding -er to their base form. These adjectives are exceptions that must be memorized. Some adjectives can also use either form i.e. (gentler, more gentle, quieter, more quiet, simpler, more simple), these exceptions must also be memorized. Short adjectives that end in -ful i.e. (stressful, helpful, useful) and short past participle adjectives i.e. (lost, bored) use the adverb -more to form their comparative forms.
Long adjectives (adjectives that have 3 or more syllables) use the adverb -more to form their comparative form i.e. (intelligent, more intelligent, confident, more confident, difficult, more difficult, mysterious, more mysterious).
Long adjective examples
Ex: He looks more athletic than the last time I saw him.
Ex: She is more confident than her friends.
Ex: Is New York more expensive than Boston?
Ex: I need to be more decisive.
Comparative adjectives - in a conversation
In conversations it is not necessary to mention the noun that you wish to compare with a comparative adjective if the person you are speaking with mentions it first.
Person 1: Let's eat lunch at Applebee's.
Person 2: I would rather eat at Chili's, the food is tastier.
Person 1: We should take the subway.
Person 2: I think we should take a taxi, it's faster and more comfortable.
Person 1: Yes, but it's more expensive as well.
Irregular adjectives
Some adjectives are irregular, their comparative and superlative forms do not follow the convention of adding -er and -est or use -more and -most, instead these adjectives change unpredictably and must be memorized.
Irregular comparative adjectives examples
Ex: I feel better after I started working out.
Ex: He took the business further than we could have imagined.
Ex: This winter is worse than last year's.
Absolute adjectives
Absolute adjectives are adjectives that cannot vary in degree of intensity, these adjectives are also called non-gradable adjectives. Absolute adjectives represent states that cannot be intensified or compared, which means they do not have comparative or superlative states i.e. (dead, alive, unique, final, perfect, married, circular, etc.). For example, a noun cannot be more alive than another or be the most alive of a group, a noun can only be alive. Although these adjectives do not have comparative or superlative forms, adverbs and adverb phrases such as almost, nearly, just about, virtually, etc. can be used to say their state was close to being achieved. English students must recognize when an adjective is absolute and should avoid using them in comparative or superlative forms.
Comparative adjectives - used as adverbs
Comparative adjectives may be used as adverbs, however this is often informal and there are usually more formal ways to express the same idea using regular adverbs.
Examples - Using comparative adjectives (informal)
Ex: I work harder when I am under pressure.
Ex: I know he can run quicker.
Ex: Metal bends easier when you heat it.
Ex: Mark speaks louder when he's angry.
Examples - Using adverbs (formal)
Ex: I work more diligently when I am under pressure.
Ex: I know he can run more quickly.
Ex: Metal bends more easily when you heat it.
Ex: Mark speaks more loudly when he's angry.
Note: This is not a complete list of all absolute adjectives, however it includes many of the most common ones.
Note: Elder is not used with than to make comparisons in modern English, Older is used instead