[snowwrestler]

I don't know what to say other than that the entire purpose of written language is to carry information between people who aren't in a position to directly observe each other writing. (If they were, they could just talk and would not need to write.)

[1787]

There exist counterexamples in the broader world. Historically in the Sinosphere it was commonish that two people might share a command of written Classical Chinese but not really be able to speak to each other. For a modern example, consider the paper below: https://eric.ed.gov/?id=ED515291