Tldr A British English, O American English
A is also the way the inventor of the term spelled it, the way it is often spelled in science and the correct Latin form.
I’m not saying O is wrong, that’s what happens in language, just adding the other points.
This is not to say that Jung wasn’t a genius. Jung was THE BOMB DIGGIDITY (which, by the way, I wish was an official term in the Oxford dictionary).
If they love Jung so much (which I agree they should because Jung was amaaaaazing), why don’t they honor him by using the spelling he actually used?
Love etymological articles with unreliable narrators.
Tldr A British English, O American English
What? How did you get to that conclusion? That’s not what the article says at all? It says Phyllis Blanchard used the (then incorrect) spelling with an O (while also changing the definition of the term to something most people I think would disagree with) in a paper she wrote and nobody knows why. And it spread from there.
I think you’re interpreting “Today, ExtrOvert is the most common spelling of the term in the United States.” to mean it’s spelled with an A elsewhere, but the author even brings up the Oxford Dictionary (UK) that says that the original spelling with an A is rare in general use. I live outside the US and I pretty much exclusively see the O-spelling.
EDIT: Changed from “incorrect” to “then incorrect” to clarify. She wrote her article before extrOvert entered the dictionary, and - according to the author of the article linked earlier in this thread - her article might have been a big contributing factor for it entering the dictionary that was published soon after.
It very clearly states that since 1918 the american spelling has been ‘extrovert’. That has nothing to do with whether the A or O is correct, only that O is more common in American English.
It also says she changed the definition, that’s the nature of language, it evolves. That can be through a colloquialism, a hard change (as this seems to be), or many other reasons.
I am not arguing whether it is correct or not, I am simply saying it is different.
Maybe I’m tired but this comment reads to me as if you’re disagreeing with me when everything you say supports what I said? My objection/question was how you came to the conclusion it’s a US/UK thing. There’s no support for that in the article.