There's a major difference - the phone network takes in prerequisite constraints on the nature of the information that it's encoding; it is forced by its functionality to be a reflection of spoken language.

The internal communications of the mind have no need for such constraints (and evolved hundreds of millions of years beforehand).

Anyway, I don't know what you were actually trying to argue here: you just built a simulated brain out of people, and the massively multi-agent distributed nature of the language of that machine is (emergently) incomparable with vocalised language.