Players don't talk for several reasons. One is lack of confidence and understanding. If they don't know what is going on, then what are they going to talk about. Players won't talk if they feel as if their communication is not being heard and acted upon. This is especially true between older and younger players.
Communication is a two way street and the coach needs to be the traffic cop.
Now we have reached the point where we start to show how to implement a flat back zone system. The following walk throughs can done before warm-ups or after a heavy conditioning session. These are the first exercises a coach should do when explaining how a zone works. D3 and D4 slide over. Now have A1 move back and A2 move forward.