In using the word "language," we have in mind the human languages that are both natural and conventional, such as English, French, German, and Swedish, They are natural in the sense that human beings are born with the potentiality of speaking and of learning them; they are conventional in the sense that the different societies in which human being are nurtured determine the language they learn and speak.
In addition to these natural languages, there are the special languages that human beings devise or invent, such as the language of a musical or choreographic score and the language of the visual arts. These are nonverbal languages, and the meaningful notations in them should be called symbols rather than signs.
Consider the language of music. What do the nonverbal symbols of a musical score mean? The notes on the page of a musical score designate the sounds to be played on various instruments or the sounds to be heard by anyone who can read the score.
The distinction calls our attention to the difference between designative signs (names in a verbal language) or symbols in a nonverbal language, such as music. But there is another dimension of significance. In addition to designative or naming significance. There are signs of symbols that function as signals.
For example, certain clouds in the sky mean the probability of rain, seeing smoke in the sky signals an unseen fire. These natural sequences are understood by us to have the significance of signals. When we use words rather than symbols, the "cry of fire" in a theater signals an unseen combustion. When the cook at a lumber camp shouts from the porch. "eats, come and get it," that verbal speech functions as a signal, not a designator. The natural cries of animals signal the behavior that other animals can expect to come from them or are warned to adopt themselves.
Only human beings have natural languages with designative or naming signs that signify the objects conceptual as opposed to perceptual thought; thus only human beings have syntactical language. In the laboratory, other animals that live in the world of perceptual thought can be trained to learn the meaning of a small vocabulary of designative signs. In the wild, without human intervention, other animals do not communicate with one another by means of any designative signs, but only by signaling.
The human infant learns a natural language in two ways. One is by learning the meaning of words that name or designate perceptually present objects. The other is by verbal description. When a child hears the word "kindergarten" for the first time, he or she may ask, "What is kindergarten?" He or she learns the meaning of that word by being told that a kindergarten is a place where little children go and learn to play with one another.
This is the ground for saying that only human beings have a verbal language that enable them to communicate with each other not only about the objects of perceptual and conceptual thought but also about objects than cannot be perceived or imagined, such as truth, goodness, and beauty; liberty, equality, and justice