Adverbs describe verbs, adjectives, or other adverbs. In English, many adverbs answer questions like how, when, where, or to what degree. The most common way to form an adverb from an adjective is by adding -ly. Not all adverbs end in -ly, but -ly adverbs are the main pattern for regular formation.

To form an adverb from a regular adjective, add -ly to the adjective. This pattern creates words that describe how something happens. The spelling stays the same for most adjectives.

Word/Phrase	Definition
quickly	The adverb of quick describes how something happens.
slowly	The adverb of slow describes how something happens.
carefully	The adverb of careful describes how something happens.
quietly	The adverb of quiet describes how something happens.

When an adjective ends in -y, change the y to i and add -ly. When an adjective ends in -le with a consonant before -le, change the final e to y. When an adjective ends in -ic, usually add -ally instead of just -ly.

Rule
If an adjective ends in -y, change y to i and add -ly.
If an adjective ends in consonant + -le, change -le to -ly.
If an adjective ends in -ic, usually add -ally.

Adjectives ending in -y drop the y, add i, and then add -ly. This rule keeps the pronunciation and makes a regular adverb form. It applies to common words in everyday English.

Word/Phrase	Definition
easily	The adverb of easy follows the -y to -ily rule.
happily	The adverb of happy follows the -y to -ily rule.
noisily	The adverb of noisy follows the -y to -ily rule.
angrily	The adverb of angry follows the -y to -ily rule.

Adjectives ending in consonant + -le form adverbs by changing -le to -ly. The result is an adverb with a different ending and often a clearer connection to the adjective. This rule is common with simple and regular adjectives.

Word/Phrase	Definition
simply	The adverb of simple changes -le to -ly.
terribly	The adverb of terrible changes -le to -ly.
possibly	The adverb of possible changes -le to -ly.
responsibly	The adverb of responsible changes -le to -ly.

Adjectives ending in -ic usually form adverbs by adding -ally. The spelling becomes -ically, not just -icly. This pattern is especially common with academic and formal words.

Word/Phrase	Definition
basically	The adverb of basic uses -ically.
historically	The adverb of historic uses -ically.
typically	The adverb of typical uses -ically.
logically	The adverb of logic uses -ically.

Some common adverbs do not follow the -ly pattern. Good becomes well, not goodly. Fast, hard, and late can be both adjectives and adverbs without changing form. These words are high frequency and must be learned as fixed forms.

Word/Phrase	Definition
well	The adverb of good is well.
fast	Fast is an adjective and an adverb with the same form.
hard	Hard is an adjective and an adverb with the same form.
late	Late is an adjective and an adverb with the same form.

Adjectives describe nouns, and adverbs describe verbs, adjectives, or other adverbs. In English, -ly usually marks an adverb, but some words without -ly can still be adverbs. The function in the sentence determines whether you need an adjective or an adverb.

Rule
Use an adjective to describe a noun.
Use an adverb to describe a verb.
Use an adverb to describe an adjective.
Use an adverb to describe another adverb.

Most English adverbs are formed by adding -ly to adjectives, with spelling changes for -y, -le, and -ic endings. Some common words are irregular and do not use -ly. Choosing between adjective and adverb depends on what you are describing in the sentence.