My first year at uni:

Me: "How about that James guy, huh? He's obviously fought his way past disability, what a great guy, an example to all of us."

"What do you mean?"

"Well, he's a professor at Oxford, that's quite some achievement"

"So what?"

"Well, I mean, you know, he's gotten past his handicap. You can kinda hear it on him, right?"

"He's Brummie..."

"Is that like a palsy or something?"

"No, there's nothing wrong with him, he just comes from a certain area near Birmingham"

"Ah. I'm gonna go find a rock to hide under."

A few years later, around when I got married:

"Hey Nacho, where are your in-laws from? Your mom and I tried to talk to them"

"They're from Scotland"

"What language do they speak?"

"English"

"What, really? I tried to talk to your father-in-law, I couldn't understand anything!"

"..."

I had the opposite confusion. I asked the sysadmin where he was from, I had guessed Germany. He told me he was from Madrid, just had to relearn speaking after he had a brain tumor removed a few years before.