Telephone Homophones

Before Christmas, I was talking to my sister J on the phone. She asked if she could talk to M to see what he thought of her idea for a Christmas gift for me. Afterward I found out that the conversation went something like this:

J: Do you think Gretchen would like a mandoline for Christmas?
M, with a puzzled expression: Uh... no.
J: Do you know what a mandoline is?
M: Do YOU know what it is?
J: Yah, I just thought she might like one since she doesn't have one.
M: Why would she want one?
J: All right, never mind. I guess I'll come up with a different idea.

Now I already had an inkling that J was thinking of getting me a mandoline, and I loved the idea, so I was horribly curious. Even though I only heard M's side of this conversation, I was almost sure I knew what had happened. You see, I am fluent in both M-ish and J-ese. So then M and I had this conversation:

G: So what was her idea then?
M: She wanted to get you a mandolin!
G: Why is that a bad idea? I'd love that.
M: You WOULD???
G: What item exactly are you thinking of when she says that?
M: The musical instrument that's like a lute or something.
G: Yah, I was afraid of that. She means a kitchen tool for slicing. I better call her back...