191. Human beings on this Earth can thus, by physical means, to some extent transmit information from one to another, or can be mutually conscious of each other's thoughts and conscious life. That this correspondence can take place is due to the ability of living beings to give their thought pictures "identification" in physical matter. This ability is of a timeless date and is already found in the more advanced animals, for the latter express their sensations of pleasure or pain and vague inklings about each other through oral manifestations. Through making "plaintive" sounds and "cries of fear" they express their sensations of pain in the same way as through producing other sounds they can manifest their joy or pleasure. A dog, for example, has no small talent for showing gladness with physical signs and sounds when it meets its master or other living beings it has learned to appreciate. And it would indeed mar the charm of spring and summer if those thousands of small throats in their outburst of praise, called "bird song", were suddenly silenced. And so it is that the creatures in the animal kingdom acquire the ability step by step to express their sensations of pleasure or pain as physical phenomena or signs. These gradually become known among fellow creatures whereby mutual and reciprocal understanding and communication between all of them begin to be released. And here we see the first faint beginnings of that development which terrestrial mankind, through the embryonic body of intelligence, has later evolved into what we know as "language". When human beings speak, they are uttering a great many different sounds which are recognized gradually as common signs for thought pictures, which, by these signs, become transferred to information or understanding for the listener. Because human beings have lived in various communities or independent groups in different parts of the Globe and the individual groups have not been subjected to exactly the same conditions of life or experiences so that their thought pictures have not been the same either, this has meant that in each individual group there developed a particularly suitable "sign system" for that group. In other words, each group - which in this case means each nation - now has its own particular language differing more or less from the other nations' languages. But gradually, as modern development makes communication between nations easier and makes them more and more technically and economically dependent on each other and interlinked, to a corresponding degree the contrasts in their various languages will be broken down and will turn into a common sign system for the whole world. In the future all people on Earth will come to use the same speech, the same language.