In a manner of speaking, change is constant

Most linguists agree that language has evolved but, Juha Janhunen finds, they do not agree on what that means

Recent progress in genetic science allows the issue of human evolution to be approached considerably more accurately than before. There is little doubt today that the human species evolved in Africa in the past million years and began expanding to the other continents less than 100,000 years ago. There are reasons to assume that language was the most decisive innovation in human evolution. Although language may have been present among other early hominids, the only surviving species retaining this innovation is the lineage of modern man. Language is inseparably linked to human evolution, and any discussion of the origins of man is inevitably connected with the question concerning the origins of language.

Language Origins is the fourth volume in the Oxford University Press series Studies in the Evolution of Language, which correctly implies that language, like other human capacities, is subject to the laws of evolution. The book contains 17 thematically interrelated chapters, originally conference papers, by authors who examine the origins of language from an evolutionary perspective. All the contributors agree that evolution is the right word to be used to explain the biological foundations of human language. However, as Maggie Tallerman, the editor, notes in the introductory chapter, there are many divergent opinions about what linguistic evolution is and what it is not. Perhaps unsurprisingly, the book's two sections on animal communication and the evolution of human speech as a physiological mechanism are less controversial than the book's other two, which consider the evolution of grammar and the origins of linguistic diversity.

The variety of approaches followed in the individual contributions illustrates well the inherently cross-disciplinary nature of the study of language origins. It seems that the emphasis has been shifting recently from the traditional fields of palaeoanthropology (not represented in the volume) and zoology (discussed in only two chapters) towards a dominance of computer simulations and mathematical models, as well as neurological explanations. This makes the volume especially useful reading for conventional linguists, who are generally not well equipped to discuss issues beyond grammatical theory.

Much of the controversy over the origins of language arises from the fact that language involves in parallel a biologically inherited capacity and a socially transmitted system. The main issues still being debated on the biological side concern the speed and original background of language evolution. While there is no doubt that language from the beginning gave the human species an important edge, it is less obvious whether language emerged in response to a biological need or as an accidental by-product of other evolutional trends. It is also a matter of debate whether language evolved gradually or was an abrupt innovation. The fossil evidence would suggest a gradual process, but some linguists, notably Noam Chomsky, favour sudden innovation, a view that comes dangerously close to what might also be called linguistic creationism.

Many diachronic linguists avoid the term evolution altogether when speaking of linguistic change. Although all languages change constantly, this change does not affect the human linguistic competence as a biological property, only the form and structure of the linguistic substance, which is - within limits -different from language to language. It is obvious that diachronic developments in the history of individual languages cannot be due to adaptation and selection in the biological sense. This point should not be taken too far, however. When Bernard Comrie and Tania Kuteva argue that languages develop basically by way of historically arbitrary accidents, they ignore the possibility that the principles of adaptation and selection are not confined to the biological level but also have social analogies.

In fact, the diachronic change of languages can be explained well in terms of the theory of evolution if we only accept that the mechanisms of adaptation and selection that affect linguistic substance are determined by the linguistic environment, rather than by the principle of biological fitness. When, for instance, spoken French has lost suffixal marking for the plural (as in chats ) but introduced articles marked for plurality ( les , des ), the development is not accidental but is following a trend set by the linguistic environment of the language. Linguistic fitness in Western Europe requires that a language has articles and plural marking. A language lacking these features might have difficulties surviving in the region, but it would be perfectly viable in other linguistic environments elsewhere.

An important circumstance perhaps not sufficiently stressed in Language Origins is the dimension of time. Even today, many linguists believe that it is possible to approach the origins of language with the methods of diachronic and comparative linguistics. These linguists believe that by applying the principles of linguistic reconstruction to a succession of increasingly ancient linguistic stages, it is possible to arrive at the mother tongue of all mankind. Fortunately, no such linguists were invited to contribute to this volume. Nevertheless some of the arguments presented by the individual authors rely on the assumption that the properties of the ultimate protolanguage can be assessed by information from documented modern and historical languages. This can hardly be so, however, for the period open to diachronic linguistic inquiry represents but a minute portion of the total prehistory of human language.

We might say that human language as a biological property is a product of the Pleistocene epoch, while even the most ancient protolanguages that can be reconstructed from extant linguistic substance date back no longer than the early or middle Holocene. What we can conclude from the available evidence is, however, that linguistic substance is subject to constant and relatively rapid change, and that the principles of this change must be as old as human language itself. Another important conclusion is that all natural languages are likely to involve an equal degree of complexity, though the specifics of this complexity vary. As all languages are products of innumerable cycles of typological restructuring and material regeneration, there can be no language that could be identified as systematically simple or typologically stable. This is also true of the so-called creoles, an unfortunate misnomer.

Under such conditions, all attempts to reconstruct the properties of the earliest forms of human language are bound to remain unverifiable and speculative. An example of such unverifiable speculation is offered by the theory of Andrew Carstairs-McCarthy, who regards the clause as an analogy to the syllable, and morphology as a derivative of allomorphy. A more likely, though equally unverifiable, evolutionary sequence of the principal components of language would be: lexicon

syntax

phonology

morphology.

However this may be, it is important to realise that the lack of morphology, including allomorphy, in some languages does not represent an archaic survival, but rather simply a random typological feature. For instance, Classical Chinese represents a language type without morphology, but traces or elements of morphology are present in both pre-and post-Classical Chinese.

An outgrowth of the idea that modern languages preserve direct survivals from the earliest stages of human speech is the theory of universal grammar. In this framework, all natural languages are supposed to reflect an inherited grammatical faculty that is uniform for all languages and may have a genetic basis. As long as the existence of grammar genes or, for that matter, of universally valid grammatical "deep structures" has not been verified, there is no reason to believe that this view is correct. A good alternative is offered by the mirror system hypothesis developed by Michael Arbib and Michael Studdert-Kennedy, who identify human language, including sign language, as an extension of the neurophysiological mechanisms connected with manual grasping. This hypothesis is congruent with the fact that early hominids had material culture, such as stone tool-making, without necessarily having an articulated language of the modern type.

Although the existence of linguistic universals is highly controversial, it is interesting to note that the continuing wave of linguistic extinction in the world is leading to a decreasing linguistic diversity and, hence, to an increasing similarity of the remaining languages. It seems to be a fact that many exotic structural features such as the dual and the ergative are vanishing today simply because the languages that have them are being lost.

This aspect of linguistic evolution, which may ultimately result in the degradation of mankind into a single huge speech community speaking a uniform language - perhaps a future form of English - is not much discussed in this volume, but it deserves to be remembered when we think of the origins of human language. Diversity has been a guarantee of evolutive success in the biological world, and it is also probably so in the world of languages.

Juha Janhunen is professor and chair of East Asian languages and cultures, University of Helsinki, Finland.