English has four major word classes: nouns, verbs, adjectives, and adverbs. Of these four classes, nouns are the largest, followed closely by verbs. Nouns are people, places, and things, such as cars, island, or engineer. Verbs are actions, including to write, to listen, and to drive. Adjectives are words that modify nouns: a green car, a smart engineer. Finally, adverbs can modify verbs and adjectives: walk quickly, a very tired puppy. However, there's more to it than just those four word classes. English is unique in a couple of ways. First, English speakers sometimes create new words by turning nouns into verbs. For example, in the sentence "We mothballed the project," the word mothball (originally a noun) was turned into a verb. Second, especially in everyday spoken English, people often use adjectives instead of adverbs. For example, "you drive too fast," where fast (an adjective) is used to modify the verb rather than quickly (an adverb).