ACT® · English: Punctuation Conventions
Punctuating Nonessential Appositives and Clauses
A noun phrase or clause gets commas on both sides only when the information is extra, not needed to tell which person or thing is meant. If it's the only thing identifying the noun, no commas at all.
Commas around a phrase or clause work like handles: they announce that you could lift that chunk out and the sentence would still name the exact same person or thing. 'My sister, who lives in Reno, called' only works that way if the speaker has one sister. The name is already fixed by 'sister,' so the clause just adds a bonus fact, and commas mark it as removable.
Flip the situation and the punctuation has to flip too. If someone has three sisters, 'sister' alone doesn't tell you which one. Now the clause 'who lives in Reno' is doing identifying work, picking one sister out of three, so it fuses directly to the noun with no commas. Same words, opposite punctuation, because the job the clause is doing changed.
Appositives, the renaming noun phrases like 'the director of the clinic' or 'the novel Beloved,' follow the identical test. 'Dr. Imani Reyes' is already a specific person, so 'the director of the clinic' is extra and gets comma handles on both sides. But 'the novel Beloved' identifies which novel out of many Toni Morrison wrote, so it's essential and takes no commas. This is the same joint logic that governs interrupters elsewhere in punctuation: anything removable gets handles, anything load-bearing doesn't.
Key terms
- Appositive
- A noun phrase placed next to another noun that renames or describes it.
- Nonessential (nonrestrictive)
- Extra information that could be deleted without changing which person or thing is meant.
- Essential (restrictive)
- Information required to identify which specific person or thing is meant, with no separating commas.
- Comma handles
- A pair of commas that mark a chunk of a sentence as removable extra information.
Watch it explained
- How it worksHow do commas around a clause announce that the information is extra rather than identifying?
- Going furtherWhat happens to meaning when a writer has three sisters and those commas stay in anyway?
- Worked exampleWalk me through punctuating 'The novel Beloved won a Pulitzer' when the author wrote many novels.
- Common mistakeWhy isn't an appositive always set off, given that most appositives you meet do carry commas?
- Ties togetherHow does a nonessential comma pair relate to the handles that lift an interrupter out of a sentence?
Check yourself
End of topic.