The document discusses the main word classes in English including nouns, verbs, adjectives, adverbs, pronouns, prepositions, conjunctions, and determiners. Nouns refer to people, places, things, ideas or qualities. Verbs describe actions. Adjectives describe nouns and adverbs provide more information about verbs, adjectives or other adverbs. Prepositions describe position or time. Conjunctions connect phrases or sentences. Pronouns are used in place of nouns. Determiners introduce nouns.