by Ulla Hedeager

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The assertion that humans differ from animals in their use of language has been thesubject of much discussion as scientists have investigated language use bynon-human species. Researchers have taught apes, dolphins, and parrots varioussystems of human-like communication, and recently, the study of animal languageand behaviour in its natural environment rather than in the laboratory has increased. It is my aim to discuss human language within an evolutionary perspective, to step across disciplinary boundaries of different fields of science, and to show how we may consider language only as one of the many forms that animal communication has taken and that it may not be out of reach of other species.

What is language? A universally accepted definition of language or the criteria for its use does notexist. This is one of the reasons for the disagreement among scientists about whethernon-human species can use language.In nature we find numerous kinds of communication systems, many of which appear to be unique to their possessors, and one of them is the language of the human species. Basically, the purpose of communication is the preservation, growth, and development of the species (Smith and Miller 1968:265). The ability to exchange information is shared by all communication systems, and a number of non-human systems share some features of human language. The fundamental difference between human and non-human communication is that animals are believed to react instinctively, in a stereotyped and predictable way. Mostly, human behaviour is under the voluntary control, and human language is creative and unpredictable. It is generally assumed that only humans have language. Parts of the problem of differentiating man from the other animals is the problem of describing how human language differs from any kind of communicative behaviour carried on by non-human or pre-human species. Until we have done this, we cannot know how much it means to assert that only man has the power of speech. (Hockett 1967:570). In order to contrast human language with animal communication, the linguist Charles Hockett (1967:574-580) introduces a generally accepted check list for language, a set of design features that all human languages possess. His seven key properties are: duality of pattern (the combination of a phonological system and a grammatical system), productivity (the ability to create and understand new utterances), arbitrariness (when signs/words do not resemble the things they represent), interchangeability (the ability to transmit and to receive messages by exchanging roles), specialization (when the only function of speech is communication and the speaker does not act out his message), displacement (the ability to refer to the past and to things not present), and cultural transmission (the ability to teach/learn from other individuals, e.g. by imitation). Until recently, articulate speech was also considered crucial to language, and the visual grammar of sign languages was not studied or recognized as true language. One famous view of language is that of the influential Noam Chomsky. He assumes that a kind of language organ within the mind is part of the genetic make-up of humans. A system which makes it possible from a limited set of rules to construct an unlimited number of sentences is not found in any other species, and Chomsky believes that it is an investigation of this uniqueness that is important and not the likeness between human language and other communication systems (Wardhaugh 1993:18-26,60-65). Apparently, linguists should not be concerned with this question because it is outside their field, and it is outside their field because the linguists themselves have defined language as uniquely human. This approach does not operate within an evolutionary perspective and does not consider language within its natural social context. Through ages, philosophy and religion have established mans place in nature, and humans tend to regard nature as the raw material they exploit and manipulate to suit their purposes, not something they should communicate with. In any case, without having intensively investigated any form of animal communication that may resemble human language, e.g. combinations of words/signs, intonation, and body-language, within a natural social context, we cannot claim that language is unique to the human species.

Where does human language come from? Language, being an efficient human adjustment to the environment, evolved bynatural selection. This seems indeed the most likely scientific explanation, andunless we believe in a divine origin, there should be no reason to reject a Darwinianpoint of view. Assuming that new species would emerge when an adaptive variation improved their survival capacity (Wardhaugh 1993:34-36), Darwin argued that the theory of natural selection could explain the evolution of instincts, too. The instincts of animals are prewired in the nervous system, and some of the brain cells, feature detectors, respond to certain kinds of stimuli (Wardhaugh 1993:100-102). Similarly, language is prewired in the nervous system of humans, and the human speech detectors are responding to language. Thus we may regard the Chomskyan language organ as a language instinct (Pinker 1995:17-20). Supporting the Darwinian theory, the embryology reveals structural resemblances between the embryonic stages of quite different species, descending from a common ancestor from whom they have inherited these almost identical stages (Parker 1995:43-50). Other important complements are the studies of genetics, the discovery of the cell nucleus containing chromosomes and a genetic code revealing a common pattern that is shared by all organisms (Husen, Petersen, and Sonne-Hansen 1983:128), the studies of homologous anatomy, and the comparative studies of the molecular structure of living species. In Eric Lennebergs view (Smith and Miller 1968:219-225) language has a biological foundation. He argues that the human organism matures according to a fixed maturational process, and that language develops in children during this period. The earliest sounds of a human infant are stimulus controlled (Fromkin and Rodman 1998:319-328). It has a mammalian larynx that can rise, enabling concurrent breathing and eating, and not until the age of three months are its speech organs ready for producing vowels (Pinker 1995:354). Around the age of six months the infant begins to experiment with sounds, and soon after it begins to babble in syllables and to imitate intonation patterns. One year old it produces one-word utterances and sentence-like gibberish, and around eighteen months the first two-word utterances occur (Pinker 1995:265-268). The first utterances longer than two words consist of open-class words carrying the main message. This telegraphic speech is supposed to represent the grammar at that particular stage of the childs language development. Perhaps linguistic accomplishments like babbling, first words, and grammar require minimum levels of brain size, long-distance connections, and extra synapses, particularly in the language centres of the brain. (Pinker 1995:289). Language acquisition may be like other biological functions, and the differences between the pre-linguistic and post-linguistic stages are caused by the maturation of the individual. Human brain growth is incomplete at birth. The brain-maturation process of all other species reach the adult state at a quicker pace, and the human brain differs in appearance as it has more surface folding of the cortex (Smith and Miller 1968:239-245). Nature tends to improve on former models and processes by building new structures upon the old ones. Mammals and birds descend from reptiles, and the structures of the reptiles brain are still present as the central parts of the adult human brain as the development of the human brain is an enormous enlargement of the cerebral cortex which is barely visible in the reptiles brain (Ellegaard 1982:25-31). The brains of all higher animals are divided into two cerebral hemispheres, and research has shown hemispheric lateralization in humans and other species, too: The control of song is strongly lateralized in the left hemispheres of many birds, and the production and recognition of calls and squeaks is somewhat lateralized in monkeys, dolphins, and mice. (Pinker 1995:306). In the left hemisphere of the human brain two areas of the cerebral cortex have been identified as important for language (Nathan 1982:226-230). Neurologists have observed that people with damage to these parts of the brain show specific language difficulties. Wernickes area appears to be essential for understanding and producing words, Brocas area to be important for grammar and sentence production. In most people these areas are larger in the left hemisphere than in the right hemisphere. Gannon, Holloway, Broadfield, and Braun (1998:220-222) have examined the area corresponding to Wernickes area in chimpanzees in order to determine if their brain structures show the same asymmetry between the hemispheres. Because language is considered unique to humans, it has been widely assumed that the asymmetry, in particular in Wernickes area, was also unique to humans and that chimpanzees lacked the structures necessary for language development. However, the surface of this area was measured and the left area was found to be larger than the right area of the chimpanzee brains. Humans and apes adapted the system of communication from a common ancestor to suit different specialized needs, and it seems that the old structures of the human brain have been used for new tasks as humans developed a specialized way of learning in order to acquire language. The human cortical areas have analogous areas in the brains of other species, who may also have been ready for some primitive kind of language.