Communication allows people to exchange thoughts by one of several methods. There are auditory means, such as speaking or singing, and physical means, such as sign language, touch, or eye contact.
As developed below, communication happens at many levels (even for one single action), in many different ways, and for all beings, and some machines. Many or all, fields of study dedicate some attention to communication, so when speaking about communication it is very important to be sure about what kind of communication are we speaking about, mainly: what type of things are communicated, between what agents, and with what kind of results.
