To spread awareness of the original meaning:

(From Wikipedia) To "beg the question" (also called petitio principii) is to attempt to support a claim with a premise that itself restates or presupposes the claim.[6] It is an attempt to prove a proposition while simultaneously taking the proposition for granted.

When the fallacy involves only a single variable, it is sometimes called a hysteron proteron[7][8][9] (Greek for "later earlier"), a rhetorical device, as in the statement:

    "Opium induces sleep because it has a soporific quality."[10]

Wikipedia marks the popular use "invites the question" as vernacular.

This seems wrong: The Oxford dictionary lists a) the original meaning and b) "invites the question", and b) is not marked as vernacular.

It's really not muddier with this use of the phrase; some people make a show about being bothered by it so they can demonstrate that they knew the original meaning.

Based on the context, you know exactly which meaning of the phrase is intended here, and it's disengenuous to pretend otherwise. The differences in context between the two meanings make this a non-problem.

rather than this usage being unclear, i think the muddiness is more about the original concept becoming more difficult to reference- it has a name, but that name now refers to a much less subtle concept

I get it, it's like when someone mentions a slippery slope: are they talking about a fallacy, or a surface I can slide down?

> Based on the context

Personally speaking, it's not always easy to tell which "begging the question" someone means from context. I often have to stop and ask "hold on, do they mean the premise assumes the conclusion?" (And all the worse for me if they just mean "brings up the question", because I'll spend a minute making sure I'm not just missing the fallacy).

In that sense, it's not quite the same as "slippery slope," which doesn't get used literally much anyway.

"assuming the conclusion" is a much better way to refer to the original concept, IMO.

It's just a common mistake. "Raises the question" would have been the appropriate idiom. In any case no harm no foul.

Not in itself. But when GP wishes that more people knew the meaning of the set phrase "begging the question", there's an underlying desire (which I share) that more people be familiar with elementary parts of logic and debate. In that sense I also wish more people knew what "No true Scotsman" or"non sequitur" mean. Including, I'm sure, myself, in all my areas of ignorance.

The words "begging" "the" "question" has almost nothing to do with what the full expression means, making it unnecessarily confusing. "circular argument" is much clearer.

A circular argument begs the question "oh, does it?"

"Begging the question" to someone with no sense of its etymology just sounds like it should mean "necessitates the asking of a question" or "makes clear a question" as opposed to "attempting to prove something whilst taking its truth for granted".

I'd imagine that we come to know the meaning of >99% of words and expressions through usage, so it feels like a fairly expected -- and reasonable, yet wrong -- outcome.

I think the form "beggars the question", i.e., left the question in poverty, unanswered, is somewhat less misinterpretable. https://en.m.wikipedia.org/wiki/Begging_the_question