Linear A seems to derive from cretan hyeroglyphs https://en.wikipedia.org/wiki/Cretan_hieroglyphs What do cretan hyeroglyphs come from? And how does a population create a language? That's absurdly difficult to initiate.
I assume you mean "writing system" and not "language" here. Writing systems were independently invented no fewer than three times (Mesopotamian, Chinese, and Mayan are unquestionably independent inventions) and probably more times, while also being reinvented from scratch numerous times after that (Cherokee being perhaps the most well-documented such reinvention--Sequoyah knew of writing from the Americans, but had n…
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"Note that being able to represent any phonetic utterance of a language is the distinguishing characteristic between proto-writing and writing."
Huh... does Chinese meet that criteria? https://en.wikipedia.org/wiki/Logogram#Differences_in_proces...