I came across the discussion about the language “Magadhi”
From a Venerable Waharaka Thero desana that I came across over a year or more ago. If my memory serves me correctly (I could have forgotten the exact details), but I believe it was mentioned that Magadhi is the Brahma’s language (in the Brahma’s realms), a universal language. It’s the language we living beings communicated with before we devolve into the lower realms.
If I come across the desana again, I’ll post it here.