Esther is the subject of the sentence. It is also a noun. The word sister is renaming Esther. It is a noun that gives us more information about Esther. Both words are referring to the same person.
So, sister is a noun that renames another noun, Esther.
Do you know much about phrases? Phrases are groups of words, without both a subject and a verb, that come together to act as one part of speech.
Esther, my sister with dark hair, sang a song.
The appositive is the single word that is doing the renaming (sister).
The phrase is that single word plus all of the words that are modifying it (my sister with dark hair).
Nonessential or Essential? (+ How to Punctuate Them)
There are two types of appositives (nonessential and essential), and it's important to know the difference because they're usually punctuated differently.
Nonessential - Use Commas
Most are nonessential. (These are also called nonrestrictive.) That means that they're not an essential part of the sentence, and sentences would be clear without them. Set these apart from the sentence with commas.
My sister, a French teacher, studied in France during high school.
My mom, a talented woman, recorded a lullaby CD.
Note that some publications don't add commas to these if they are simply a name.
My husband David is allergic to cats.
People who always add commas to nonrestrictive appositives would insist on using commas in that example since I only have one husband! However, some publications ignore using commas in this situation.
Essential - Don't Use Commas
Some are essential to the meaning of the sentence. (These are also called restrictive.) If these weren't in the sentence, the meaning of the sentence would be unclear.
The movie Moonlight won best picture in 2017.
The author Victor Hugo was born in France.
Do you see how we need those in order to understand the meaning of those sentences?
Intensive pronouns are used to emphasize another noun or pronoun. We can also call these emphatic appositives. Never use commas with these.
I made a sandwich for the president himself.
My sister herself paid for my popcorn.
To diagram these, put them in parentheses after the noun that they're renaming.
Add any words that modify it on slanted lines just like other modifiers.
We love this program! I cannot tell you how crazy impressed I am by how professional it is.
My kids, who were not looking forward to this at all, went nuts after watching the first video. They loved your energy, and consequently they did not miss a single lesson even though I never reminded them to do anything.
- Catherine, Homeschool Mom
learned more about grammar in your awesome 59 minute talk than I ever
did in school. If only we had teachers like you back in the 70's when
they were trying to teach me this. I was baffled by the diagramming stuff
until just now. Thank you! :)
Thanks for being a part of the Grammar Revolution!
Our Free Guide Gives You A Fun Way
To Teach And Learn The Basics v
Elizabeth O'Brien is the creator of Grammar Revolution.
Her lessons are guaranteed to give you more confidence in your communication skills and make you smile. :)