A friend posted this meme. I would add:
You are correct, duplication is vital to true communication.
A duplication at the receipt point of that which emanated from the source point IS part of the definition of communication and is largely the responsibilty of the source point. But to the degree that the receipt point is paying attention and has the intention to receive the communication.
That can and often does go off the rails because the communication is out-gradient for the receiver. So the challenge to those who would truly communicate is to continually be looking for the correct gradient for the person or audience to whom they are communicating, or attempting to communicate and adjust what they say and writing so it… …communicates!