Short answers, pulled from the story.
The first known example of written language is a clay tablet from Uruk dated to the end of the 4th millennium BCE. This artifact emerged as Mesopotamians needed a way to track livestock and commodities that exceeded human memory capacity.
A community of Canaanite turquoise miners in the Sinai Peninsula invented the alphabet once in human history to write West Semitic languages. They adapted concepts and at least some written letterforms from Egyptian hieroglyphic writing while adopting wholly West Semitic sound values for their letters.
Plato expressed concerns in his dialogue Phaedrus around 348 BCE that reliance on writing would weaken memorization abilities since written words create forgetfulness in learners souls. Written language facilitates preservation and transmission of culture across time allowing societies to develop sophisticated law and education structures.
Marshall McLuhan presented ideas about written language in The Gutenberg Galaxy published in 1962 arguing that printing press invention fundamentally changed human society nature. He suggested this shift from oral tradition to written culture led to rise of individualism nationalism and other aspects of modernity affecting consciousness globally.
Chinese script originated around the late 2nd millennium BCE evolving from oracle bone script used for divination purposes during the Late Shang period. Logographies represent a language units of meaning as words or morphemes though still associated by readers with given pronunciations in corresponding spoken languages.