|
|
|
|
|
|
|
|
INTRODUCTION
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 ?
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 ?
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.
|
