Our Greatest Possession Man is called in Greek the Zoon phonanta which means the【1】______. What 【1】______ makes humanity diff

Man is called in Greek the Zoon phonanta or talking animal. What makes humanity different from the rest of the animal world is its capacity for constructing a system of sound signals. You will say at once that certain birds talk and some of them talk very well. Chimpanzees can be taught a number of words and a few simple grammatical structures. But only human beings are able to invent whole languages, not merely parts of them or handle a few nouns and verbs. When an animal began to talk, that animal called itself man.
  Speech certainly came before the discovery of fire. We still tend to use speech not for conveying messages or expressing feelings but merely for establishing and sustaining human contact.
  The act of speaking serves primarily the end of sociability. It does not have to mean anything but it has to be continuous. At dinner parties a prolonged silence is the most embarrassing thing in the world: it seems to indicate that sociality has failed. It is often broken by more than one person’s speaking at the same time--excuse  me--sorry--after you--no, after you--and what is said is far less important than the fact of somebody having said something, anything. Everybody breathes a sigh of relief, especially the hostess.
  We have no means of knowing what the language of, say, Stone Age man was like, but we know something  of that ancient language known as Indo-European because its structure and some of its vocabulary, much changed, survive in the daughter language, which means most of the languages of Europe. It seems to have been a complex language, with a rich grammar, not at all like Malay or Chinese, and it is fairly certain that the further back we go in our study of language the greater complexities we find.
  The simplification of language is essential]y a part of the modernization of language: modern English is grammatically much simpler than its ancestor Anglo-Saxon, and Italian and Spanish are much simpler than their mother Latin. It is wrong to think of the first talkers taking a few linguistic bricks, joining them together, then baking more bricks and adding them to make a more and more imposing structure. An original babble was associated  with a particular feeling or thought, but it was only in the period after, say, the break-up of the Roman  Empire that grammarians began to analyzes the parts of this babble and come up with terms like noun, verb, adjective, adverb.
  All of us say things we never said before, and without much conscious effort; we are always inventing new things to say. That is the great human talent. This talent is based, however, on a very simple peculiarity of the human brain--its capacity to think in opposed structures.
Look at it this way: the spectrum has many colours in it, and one is merged into another. Man learned to pick out colours as separable items. He did more; he learned how to make them into signs of opposed meaning.  You have only to think of a traffic signal to see that this is so. Now out of the babble of noise which the human vocal system is capable of producing it is possible to separate specific sounds and oppose one to the other. Pick does not mean the same as pig, because/k/is opposed to/g/, though those two sounds only differ (in English, anyway)in that one is breathed and the other sung. This structuralist gift of the human brain enables us to talk of tiny structures that oppose each other in doing separate jobs and, taken together, add up to a language.
  We are, it has to be confessed, almost totally ignorant of the origins of human language, but we do know that it was the evolutionary breakthrough which produced the species we call man. And when language first appeared it was already fully grown. The system of symbols of the outside world which includes our own bodies was the key to the creation of inside worlds--sciences and technologies. Language is our greatest possession. We would be wise to think about its mysteries and cherish the miracle that language is. But we will never be able to understand it.