[calf]

Yes but Regular Mandarin has different tones, Beijing Mandarin is not Hong Kong-style Mandarin is not Taiwanese Mandarin and so when a foreigner chooses "Reference Mandarin", they are choosing what, exactly?

Point being, this idea of a Universal Reference is exactly the kind of linguistic erasure that is wrongheaded to begin with. Nor does this completely prevent comprehension, these debates underestimate how much human communication is contextual, you read what I wrote above and most of it was your mind already filling in (gasp, like an LLM) the next words enabling you to read relatively quickly.