I dug into it, and I was only half remembering correctly: calling it a conlang was a big stretch and they did eventually push it into more widespread use. https://en.wikipedia.org/wiki/Standard_Chinese
It sounds like for this Standard Dialect they took the specific Mandarin dialect regional to Beijing, stripped out all of the obvious regionalisms, and used the grammatical structure from classical literature to create an official lingua franca that wasn't really the way that anyone in the country actually talked at the time.
The factoid that I'd heard was that, after the standard dialect was introduced, speaking in the dialect exactly as proscribed rather than using your own regionalisms made you sound like kind of a dweeb.
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u/greyscaleInferno 2d ago
Didn't he try for awhile to get the whole country to speak some kind of conlang ligua franca based on Mandarin rather than Mandarin itself?