Comunication is to know about each other ,is to have knowlege of situations, times, problems and even personal information of each other. lets take the example of language, if we go somewhere we still dont know about others as well as they will also dont know ,if both don't understand language of each other, but when we will use the language which others can easily understand then it means we comunicate by each other. Comunications is just to know Something.

Hope it will help you..