While walking the dog during the most recent warm day — a few days ago now — I passed a knot of grade-school kids and their bicycles across the street. I didn’t pay them much attention, but after I’d passed by, I clearly heard one of the boys say, directed at one or more of the others, “See you later, alligator! After a while, crocodile!”

People still say that? Kids still do? It sounded old even when I was young, though I can’t say I heard it much. Later I heard the mid-50s song of that name, recorded by Bill Haley, which seems to have popularized the phrase, but not invented it.

I’d always imagined it was from the ’20s. It sounds like it belongs in the same league as the bees’ knees or 23 skidoo or the like, but after looking around a little, its exact origin and timing remain elusive. One source speculates it started with Swing devotees of the late ’30s, which is plausible, but who knows?

On the other hand, I do know that the phrase lives on in the 2010s. Maybe some celebrity who appeals to kids is saying it now.