Verbs say what happens; adverbs often say how, when, or to what degree. An adverb modifies a verb, an adjective, another adverb, or sometimes a whole clause.

Many English adverbs end in -ly, but many do not: often, very, well, not. Their position is freer than that of adjectives, so they can appear in several slots within a clause with only slight shifts in emphasis.

Learners sometimes over-produce -ly forms or misplace frequency adverbs. Semantic classes of adverbs interact with tense, aspect, and negation. In some languages one form serves as both adjective and adverb.

• Modifier of verbs, adjectives, or adverbs
• Expresses manner, time, place, degree, or frequency
• Position relatively flexible
• Not always marked by a special ending