I don't clearly understand the differences between 우리들, 우리, 저희.
I mean, I see that 우리들 is the plural of 우리, but sometimes it seems like 저희 would be just as appropriate as 우리 for "my" and I can't tell when to use 우리들 as opposed to 우리 for "our".
저희 is the honorific form of 우리 like if you were speaking to your mother who you respect/someone older than you then use 저희 vs a friend/ colleague/ same age as you use 우리
I guess that is his/her question? The person addressed is already honorific, but this part of the sentence isn't. Confusing.
So, this is the one time the "our" in front of grandma really means "our..."?
It's because 들 (plural) is attached to 우리 so you can tell there is more than one person for sure
I guess in this case it isn't also. the speaker says with "-요?" then it implies the listener is older than the speaker. Therefore the woman who is grandma of speaker can't be the listener's grandma.
In this case, I think you know this already, our only includes speaker.
The woman is the grandmother of the speaker. Grandma is informal language, even in the USA where the younger generation has often never been taught to have respect for their elders or superiors.
The notes say that 할머니 is plain and 할머님 is honorific, but I have seen both used in the exercises here in pretty much the same context. How do we know when to use the plain form? Aren't honorifics always used to talk about older relatives? Like in this sentence, 계세요 is in honorific form, so shouldn't 할머님께서 be the form used?