When Ruhlen's ‘mother tongue’ theory meets the null hypothesis Louis-Jean Boë † , Pierre Bessière ‡ and Nathalie Vallée † † ICP Université Stendhal, INPG, CNRS, Grenoble, France ‡ GRAVIR, CNRS, Grenoble France E-mail: boe@icp.inpg.fr, Pierre.Bessiere@imag.fr, vallee@icp.inpg.fr ABSTRACT The demonstration of a relationship between languages can depend on finding words of similar phonological shape and roughly equivalent meaning. But it must be shown that the similarities observed could not have arisen by chance. That is to say, the null hypothesis can be rejected. We demonstrate, by a simple application of probability theory, that the world roots proposed for a Proto-Sapiens language by Merritt Ruhlen in The origin of Languages are the result of random chance. The null hypothesis can not be rejected. The author used too few roots, too many equivalent meanings, too many languages per family, and too many phonological equivalences for a too small number of different phonological shapes. Our calculating the factor of chance in multilateral language comparisons is a general procedure than can be used to test the limits of the methodology of Greenbergian mass comparisons. 1. INTRODUCTION At present, there is a considerable literature showing in detail that criteria for determining a match both semantically and phonologically are almost entirely lacking, and there are numerous publications arguing against multilateral comparisons [1-7]. These numerous criticisms notwithstanding, Ruhlen’s theory of the mother tongue based on global etymologies [8-9] is systematically presented as a fact in numerous popular scientific works or magazines (Scientific American, Popular Science or in France La Recherche, Science et Avenir) [10-12]. The origin of Languages is even recommended by MIT as a reference book in language and linguistics [13]. Gell-Mann, who received the Nobel prize in physics for his work on the theory of elementary particles, wrote the preface of the collective book The Evolution of Human Language [14]. He argued that is possible to construct a family tree for all the world's languages by analyzing similarities between them. He stated that any argumentation against this possibility is “so silly on the face of it that you wonder how adult human beings can adopt it.” Some people see in the demonstration of the existence of a Proto-Sapiens mother tongue a confirmation of facts presented in the Bible: “Note how the main language branches Semitic, Turkic and Indo-European meet at just the point where the Tower of Babel may be. Not in Babylon but in the area East of the Black Sea” [15]. For almost five years, this phenomenon of propagation that Dan Sperber calls Contagion of ideas [16], has seemed to us important to analyze. We came up with a project to try to understand why some interdisciplinary fields, such as linguistics, are attracted by theories that are ill founded. We intend to investigate why there is continued propagation of such theories while the proof of their validity has not been established or even that they have been falsified. Our project is called Representation and diffusion of scientific ideas in speech and language sciences [17-18]. For centuries, theories addressing the origin of man and the origin of languages have been closely linked. In the XVII th century the old interest in the origin of language and the identity of mankind was rekindled and became a dominant subject of discussion, but in the orthodox view, the Bible was still the main source of information about the earliest history of the earth and of mankind. It was believed that the earth, mankind and human language with it, were no older than about six thousand years. By the turn of the nineteenth century, with the simultaneous developments of comparative philology and anthropology, the question of the origin of man and language has been revisited with new perspectives. In Germany and France relationship between linguistics and anthropology was very close. It could be noted that a circular argumentation was already appearing. On the one hand linguists used anthropological hypothesis to validate their assumption on monogenesis for language. On the other hand anthropologists referred to the hypothesis of a mother tongue to corroborate the assumption of monogenesis of mankind. Nowadays, “the New Synthesis” which associates Cavalli-Sforza, a geneticist [19], Renfrew, an archeologist [20], and Ruhlen, a linguist [8-9] uses the same circular argumentation to reconstruct human evolution. In spite of the numerous criticisms leveled against the methodologies adopted by Cavalli-Sforza, Renfrew and Ruhlen, the CNRS (French National Center for Scientific Research, equivalent to NSF in the USA) launched a national project entitled Origin of Man Language and Languages. It considered that the frames elaborated at the end of the eighteen century and at the beginning of the nineteen century by the Indo- Europeanists “exploded overwhelmingly” with the coming of the “New Synthesis” works [21-22]. Being part of this nation wide project we intend to test Ruhlen’s hypothesis statistically. 2. "MEGALOCOMPARISONS" For about fifteen years now, Ruhlen's works in genetic typology of languages, based on multilateral comparisons of sound shapes and meaning similarity for all languages of the world, have tried to validate the existence of global 15th ICPhS Barcelona 2705 ISBN 1-876346-48-5 © 2003 UAB