Parts of speech
Also known as: word classes, lexical categories
The parts of speech are the categories that classify words by the job they do in a sentence: noun, pronoun, verb, adjective, adverb, preposition, conjunction, and interjection. Knowing a word's part of speech tells you how it can combine with other words.
English words are traditionally sorted into eight parts of speech. Nouns name people, places, things, or ideas. Pronouns stand in for nouns (she, it, which, themselves). Verbs express action or state of being. Adjectives modify nouns and pronouns. Adverbs modify verbs, adjectives, or other adverbs, and often answer how, when, where, or to what degree. Prepositions show relationships of time, place, or direction and begin phrases like under the table. Conjunctions join words, phrases, or clauses. Interjections express emotion and stand apart grammatically (ouch, well).
A word's part of speech depends on its function in the sentence, not on the word itself. Light is a noun in "turn on the light," a verb in "light the candle," and an adjective in "a light jacket." That is why parsing a sentence means asking what each word is doing rather than recalling a memorized label.
Getting these categories right underpins nearly every other grammar rule. Subject-verb agreement requires identifying the subject noun and the main verb rather than a noun sitting inside an intervening prepositional phrase. The adjective-versus-adverb distinction decides between "she runs quick" and "she runs quickly." Pronoun case, dangling modifiers, and parallel structure all depend on knowing which category a word belongs to.
Standardized tests probe parts of speech constantly, usually without naming them. ACT English and Praxis Core Writing questions test adjective and adverb usage, pronoun choice, and agreement, while CLT grammar and writing questions ask directly about a word's part of speech and about word choice. Practice identifying the function of each word in a sentence and the underlying rules become far easier to apply under time pressure.
Key takeaways
- The eight traditional parts of speech are noun, pronoun, verb, adjective, adverb, preposition, conjunction, and interjection.
- A word's part of speech is determined by its function in a sentence, so the same word can belong to different categories.
- Adjectives modify nouns and pronouns; adverbs modify verbs, adjectives, and other adverbs.
- Most grammar rules — agreement, pronoun case, modifier placement, parallelism — depend on identifying parts of speech first.
- The ACT, Praxis Core Writing, and CLT all test parts of speech, often through usage questions rather than by name.