Language is human so it differs from animal communication in several ways. Language can have scores of characteristics but the following are the most important ones: language is arbitrary, productive, creative, systematic, vocalic, social, non-instinctive and conventional. These characteristics of language set human language apart from animal communication. Some of these features may be part of animal communication; yet they do not form part of it in total.
Language is, today, an inseparable part of human society. Human civilization has been possible only through language. It is through language only that humanity has come out of the stone age and has developed science, art and technology in a big way. Language is a means of communication, it is arbitrary, it is a system of systems. We know that Speech is primary while writing is secondary.
Language is Arbitrary: Language is arbitrary in the sense that there is no inherent relation between the words of a language and their meanings or the ideas conveyed by them. There is no reason why a female adult human being be called a woman in English, aurat in Urdu, Zen in Persian and Femine in French. The choice of a word selected to mean a particular thing or idea is purely arbitrary but once a word is selected for a particular referent, it comes to stay as such. It may be noted that had language not been arbitrary, there would have been only one language in the world.
Language is Social: Language is a set of conventional communicative signals used by humans for communication in a community. Language in this sense is a possession of a social group, comprising an indispensable set of rules which permits its members to relate to each other, to interact with each other, to co-operate with each other; it is a social institution. Language exists in society; it is a means of nourishing and developing culture and establishing human relations.
Language is Symbolic: Language consists of various sound symbols and their graphological counterparts that are employed to denote some objects, occurrences or meaning. These symbols are arbitrarily chosen and conventionally accepted and employed. Words in a language are not mere signs or figures, but symbols of meaning. The intelligibility of a language depends on a correct interpretation of these symbols.
Language is Systematic: Although language is symbolic, yet its symbols are arranged in a particular system. All languages have their system of arrangements. Every language is a system of systems. All languages have phonological and grammatical systems, and within a system there are several sub-systems. For example, within the grammatical system we have morphological and syntactic systems, and within these two sub-systems we have systems such as those of plural, of mood, of aspect, of tense, etc.
Language is Vocal: Language is primarily made up of vocal sounds only produced by a physiological articulatory mechanism in the human body. In the beginning, it appeared as vocal sounds only. Writing came much later, as an intelligent attempt to represent vocal sounds. Writing is only the graphic representation of the sounds of the language. So the linguists say that speech is primary.
Language is Non-instinctive, Conventional: No language was created in a day out of a mutually agreed upon formula by a group of humans. Language is the outcome of evolution and convention. Each generation transmits this convention on to the next. Like all human institutions languages also change and die, grow and expand. Every language then is a convention in a community. It is non-instinctive because it is acquired by human beings. No body gets a language in heritage; he acquires it because he an innate ability.
Language is Productive and Creative: Language has creativity and productivity. The structural elements of human language can be combined to produce new utterances, which neither the speaker nor his hearers may ever have made or heard before any, listener, yet which both sides understand without difficulty. Language changes according to the needs of society.
Finally, language has other characteristics such as Duality referring to the two systems of sound and meaning, Displacement which means the ability to talk across time and space, Humanness which means that animals cannot acquire it, Universality which refers to the equilibrium across humanity on linguistic grounds, Competence and Performance which means that language is innate and produced is society and furthermore, language is culturally transmitted. It is learnt by an individual from his elders, and is transmitted from one generation to another. Thus using J. Firth’s term, language is a ‘polysystametic’. It is also open to be studied from multifaceted angles.