Keladry: "I actually told a work friend today that I am on the spectrum, and she indicated that she was surprised because I "talk"..... but I talk to her one-on-one, and almost never talk at all in a group setting. "
I've had the same thing! Except I wasn't comfortable disclosing for "spectrum" with this particular person who was speaking to me, and in the context in which I needed to give information like this, I modified things to telling him I'm an "introvert."
It was part of the context of an issue we were discussing, and he was one of those people I knew that was all I could say to him rather than telling him outright about my ASD.
Well I was right not to go ahead about ASD, because clearly he didn't even properly understand simple introvertism, a concept far more commonly known!
Because when I said I am an introvert, he said "But you can talk."
Uh, YEAH . . . .I said I was an introvert, not "I'm mute/non-verbal".

Exactly. Sigh.
Funny you had that experience with describing yourself as introverted. Before I knew about my ASD, I told some colleagues that I am introverted and they didn't believe me (also because I "talk"). Sigh