I appreciate that brettd mentioned body language, facial expression, and tone of voice. Communication requires that you are both a good giver and receiver. You must be able to read the other person's body language,, facial expression, tone of voice and etc. in order to develop quality relationships.
Good communication skills project confidence and self assurance. People look at you, whether based on first impressions or lasting ones, in part based on how you communicate. This includes your body language, posture, how you look at people, how organized and eloquent your thoughts are and the inflection of your voice. It's becoming less common that people have good communication skills, so it's easier to make yourself stand out in a job interview or elsewhere when your skills are head and shoulders above the general public.
Communication is a key part of all aspects of our life. Whether it be our personal life and the relationships with each other or our professional life and the relationships with our co-workers communication is a must.
Post #2 does a good job of talking about the economic and educational aspects of communication, but your personal life requires effective communication as well.
They say that communication is the basis to every marriage because spouses need to clearly communicate their wants and feelings so that they can understand one another. This is also very important in parenting. Being able to clearly convey to your children what it is that you want from them (and sometimes why) is very important in getting them to become responsible people as they grow up.
So communication is very important in your personal life as well.
Practically every job requires communication skills, whether they are verbal or the written word. Also, in intellectual settings such as the lower grades, undergraduate and graduate levels, a student needs good communication skills to get their point across to both their peers and teachers. Interactions of a social nature require the ability to communicate effectively. Therefore, read as much as possible and your vocabulary and knowledge will expand dramatically. Instead of students texting constantly, practice having face to face verbal discourse. It will pay off in the end, big time.
The term "communication" is related to our existence as human beings, then as a society, because human beings and communication are interdependent. Without language and communication, we as human beings who are mostly interacting and relating by means of communication process, our existence on Earth would be useless.
During the speech, communication is not made only by words but also by the tone of speaker's voice, the amplitude or location of the breath, the variation in skin color (especially of the face), of speaker's attitude, etc. For example, for understanding a message, the speaker's behavior is also important.