"Melanie, my sister, and I live in the same house."
How many people live in the house? 2 or 3? I would say 3.
Thanks.
It's ambiguous grammatically.
However, your listener either knows Melanie and knows she is not your sister, or your listener doesn't know Melanie, in which case I would assume it's your sister. I would make this assumption because if the listener doesn't know Melanie, then Melanie needs an introduction as well.
My college roommate Melanie, my sister, and I ....
In real life, we interact and get clarification when it's important.
You can avoid ambiguity in written language with a tiny rewrite.
My sister Melanie and I live together.
I live with my sister and Melanie.
Melanie and my sister are both my roommates.
Yes, if Mark is your only brother and Melanie is your only sister then set them off with commas because the name is an appositive.
However, you are pursuing tiny nuances in meaning that in regular conversation are simply not that important to the point you want to make. This is one big difference in the things I post here compared to teachers -- I am focused almost exclusively on how to most easily convey your message. Anything that distracts from the purpose and message is less effective communication. And there are things that are simply not important to the story -- those become distractions instead of pushing the story along.
Consider:
A: My sister Melanie and I live together.
B: Oh, how nice. It must be nice to have someone to come home to every night.
A: Yes, though like most sisters, we do have our fights.
B: I bet. My sister lives so far away that it would be nice to have her close enough to have a fight with.
A: I'll share Melanie with you sometimes, if you want.
Or this:
A: My sister Melanie and I live together.
B: Nice. Do you have other sisters?
A: No, just her.
B: Ah, okay. I thought maybe... never mind. Do you like living with her? I fight with my sister so much I think it would be a disaster!
A: My sister Melanie and I live together.
B: Do you have other sisters?
A: No, just her.
B: Oh, I notice you didn't use commas to set off her name. That must mean that you have more than one sister.
A: Oh, no. She's my only sister.
B: Oh, see, the way you wrote that, without the commas, I would have thought you had more than one sister. Like My sister Melanie and my other sister Veronica. Get it?
A: Yeah, okay whatever. I guess you don't really care about the fact that we live together.
B: No, no. That's nice. It's nice that you live with your only sister whose name is Melanie.
What do you think is more likely? What do you think the purpose of the conversation is?
2006\
and appositives are always set off with commas. I don't agree.
Thanks.
2006
Oh, dear. Yes. My attachment to the serial comma blinds me to those possibilities.
I never, never write a list of three or more items without the serial comma. It simply wouldn't occur to me to omit it. I'm not sarcastic at all.
2006My sister, Melanie and I live together = 3 people
My sister, Melanie, and I live together = 2 people ("Melanie" is an appositive in that sentence.) I wouldn't use any commas in this sentence. With commas, many people will interpret it as 3 people living together.
2006
That's how I see the issue.Neither version is entirely satisfying, I guess. "My sister, Melanie, and I live together." requires that the reader know a thing or two about appositives I think that's expecting too much.
, while "My sister Melanie and I live together." might lead people to think that you have more than one sister. I don't think that matters. The information you are conveying is that you live with a sister named Melanie.
Neither version is entirely satisfying, I guess. "My sister, Melanie, and I live together." requires that the reader know a thing or two about appositives, while "My sister Melanie and I live together." might lead people to think that you have more than one sister.