I think that (Incas) was more numerical record keeping rather than written language.
What's special about written language (which some existing hunter-gatherer tribes still don't have), as opposed to spoken language, is that it allows cultural knowledge to be spread, stored, accumulated, and built upon.
What's special about written language (which some existing hunter-gatherer tribes still don't have), as opposed to spoken language, is that it allows cultural knowledge to be spread, stored, accumulated, and built upon.