It’s a catchphrase usually used humorously to (pretend to) distance one’s self from having even passing familiarity with something.
“OK, it’s an hour and a half before we have to head over to the shareholder’s conference, so if you want to hang out in the cafe and drink a beer and play hearts, go ahead, but keep an eye on the clock.”
“What is this ‘clock’ of which you speak?” [spoken slowly, as if English were 2nd language]
Is there a single origin, a movie or a play, which was the source of this?
It sounds like a line from a B-science-fiction movie from the '50s. An alien would not know about something We Humans (I capitalised that because the aliens would always name themselves: ‘We Brainians are a most unmerciful race.’) take for granted. For example, a Benevolent Alien might meat an Earth Girl. EG says, ‘Why don’t you give me a kiss?’ The BA, having come from a highly intellectual, ordered society, would know nothing of it. ‘What is this kiss, of which you speak?’
I think it’s a device used in those films to indicate that even though the alien race might be more technologically advanced, they have lost the simple things that make us human.
There is an instance of its usage in the English translation version of Antoine de Saint-Exupéry’s The Little Prince, originally published in 1943 (in French - I don’t know when the first English translation was published):
I would not be the least suprised that a line from as universally popular and beloved a book as that, has found its way into modern vernacular.
I often use the phrase, “what means this word, ‘_____’?” but I didn’t get it from any known pop culture source, but rather from my great-grandmother, who spoke English pretty well, but not REALLY well.
When I say it, it’s usually, “Sleep? What means this word, ‘sleep’?”
