It looks like this:
Me (carrying the downstairs phone into Athena’s room): I need someplace to put this while the new kitchen counters are installed. Do you have a phone jack in your room?
Athena: A what?
Me: A phone jack.
Athena: I… I don’t know what that is.
(Both of us stare blankly at the other for several seconds in mutual but separate disbelief)
And now you know.