Worth noting that the visual cortex already does project mental images externally using, for instance, the limbs. Human languages around the world make constant use of this, combining speech and other conventionalised modes of expression with depictions like manual gestures. The keyword here is iconicity, when the form of expressions does resemble their meaning (and this is why “our languages are symbolic” is only a very rough approximation of the truth; in actual fact, our languages are indexical, iconic and symbolic, and each of these offers its own constraints and affordances). There is a large literature in linguistics and cognitive science on the forms and functions of iconicity in human communication. And there is good evidence (from archaeology to comparative visual anthropology to linguistics) to think that human-intelligence level-language evolved exactly from such beginnings, featuring a combination of indexical, iconic, and symbolic signs.
Worth noting that the visual cortex already does project mental images externally using, for instance, the limbs. Human languages around the world make constant use of this, combining speech and other conventionalised modes of expression with depictions like manual gestures. The keyword here is iconicity, when the form of expressions does resemble their meaning (and this is why “our languages are symbolic” is only a very rough approximation of the truth; in actual fact, our languages are indexical, iconic and symbolic, and each of these offers its own constraints and affordances). There is a large literature in linguistics and cognitive science on the forms and functions of iconicity in human communication. And there is good evidence (from archaeology to comparative visual anthropology to linguistics) to think that human-intelligence level-language evolved exactly from such beginnings, featuring a combination of indexical, iconic, and symbolic signs.