If I've ever doubted that I "think like a translator", I don't any more.

I've imagined a situation in which I'm sitting down and someone else approaches me, but I don't see them until they've sat right next to me and have greeted me. And when they greet me, I turn around surprised and say "who is this?", rather than "who are you?".

It's easy enough to argue that the former "works", but for me personally it's hard to imagine what anyone would say if not the latter without thinking. And therefore I somewhat feel like a non-native speaker of English, when I've said "Who is this?"