Communication is a two way understanding through verbal and non-verbal action. If there is no understanding then there is no communication.
We communicate in two ways: verbal and non-verbal. Verbal takes the form of talking, singing, whispering or even yelling. Non-verbal can be with our hands, eyes, arms, using gestures. etc. I have heard that if you are trying to talk with someone whose arms, legs or eyes are crossed, you are not being listened to!
Communication takes place when we are able to listen with our ears and with our eyes. Sometimes when we hear silence from the person we are sharing with, we believe that they understood what we have just stated. The reality may be that the person is thinking about what you have just shared or they didn't listen. This happens so many times between spouses and with our children.