Communication is often interpreted as "talking on the field." Calls like "man on, time and turn" are viewed as evidence that a team has reached a high level it. But this is only one element, albeit an important one. Effective communication involves much more then just verbal skills.
In reading the above the it becomes clear how closely insight is involved with communication. What effect will the field have on the game? How should we play with this wind and sun? If the opponents are playing with three back players how do we want our wingers to play? Insight without good communication is like a band playing from different music sheets. Everyone can be playing brilliantly, but no one is playing the same tune.
Good communication starts with everyone being in agreement with the plan. Everyone's tasks must be clear and understood. Too often this is not the case and miscommunication results. Example. In a 4v4 match the sweeper has beaten his immediate opponent and has moved into the midfield. What should the two midfielders do? If both go ahead of the ball the available space for the top and sweeper will get very crowded. If the sweeper loses the ball who will stop the counter attack? This is a moment that the midfielders need to ask themselves "what should I do?" But that answer is partly dependent on the other midfielders' actions. If the plan is to let the sweeper through to combine with the top, then both midfielders will hold behind the ball. If one midfielder has a supplementary task of going forward, but is not in a position to do so, what should the other one do? These situations happen so quickly and are so common that they can be overlooked. There is simply not enough time to "call" instructions by either players or the coach. Communication is based on reading the situation, analyzing it and acting on it.
Next is a common vocabulary. Playing wide to one player might be 10 yards inside the field. To another it is on the touchline. Having agreement about terms makes instructions consistent. The players do not have to constantly reinvent the wheel.
Effective communication is more then "talking on the field." It is the factor that can bind a team together and allow it to be more then the sum of its parts.