The two books under review, both edited by Rudolph Botha and Chris Knight, came out of an international conference held in Stellenbosch, South Africa in November 2006. The fifteen chapters of the first volume cover the origin of language and the more general aspects of its evolution, and suggest that modern language appeared gradually between one million and 50,000 years ago; the second volume investigates, in another fifteen chapters, the African origin of human language and culture from 250,000 to 150,000 years ago. The forty scholars from different countries who made this erudite sum possible address the fossil, genetic and archaeological evidence and examine the ways these have so far been interpreted, using a variety of approaches from paleogenetics, comparative biology, primatology, behavioural ecology, historical linguistics, paleolithic archaeology, cognitive science and social anthropology. Together, they summarize many of the most significant recent research findings and developments in the field of human origins. Comprehensive bibliographies and detailed indexes enrich these two dense, sometimes arid volumes combining theoretical approaches and reports on empirical research, aptly supported by a good number of tables, plates and figures.

The first volume, The Prehistory of Language, is based on the conviction that ‘understanding how language evolved and its impact on cognition, behaviour, and culture remains one of the most demanding and important challenges facing paleoanthropology’ (p. 75). Using data gathered in primatology, the authors, considering possible reasons behind language evolution and the part humans played in it, propose that, apart from being a tool for the exchange of information, with grammar playing an important role, the main social function of language was that of bonding for group survival and reproduction. Hypotheses concerning the social role of vocal communication in the emergence of language as a complex adaptive system have received significant support from recent studies in animal communication, and results suggest that the capacity for some form of language-like communication had to be in place some 500,000 years ago, with only humans having evolved language because they only had the required cognitive abilities. Of particular interest are chapters 4 and 5 which look at similarities and differences between music and language as communicative media presented as complementary components of the ‘human communicative toolkit’ (p. 3); those two chapters, founding their hypothesis on Rousseau's Essai sur l'origine des langues (1781) and Darwin's writings, suggest a co-evolution of language and music, a theory backed by the study of tonal languages and infant-directed speech (IDS). Chapter 7 presents social play as a model for the understanding of the way language emerged as an organized system of communication. Chapters 8 and 9 offer a comparative approach to the similarities and differences between human language and the communicative systems evolved among non-human primates. The authors look at language and syntax evolution from a linguistic perspective, investigate the origins of some basic features of the human lexicon, and propose that a word-based lexicon evolved by building on ancient conceptual categories shared by primates and pre-linguistic infants. They investigate the effect of the lowering of the larynx in humans, comparing the areas of acoustic space in male and female vocal tracts, and the implications of such data for modelling the evolution of speech. The first volume concludes in confirming language as characteristic of humans alone, a skill that originated on the African continent and spread outward from there.

The second, companion volume, The Cradle of Language, is the first to focus on the African origin of human language and explore the origins of language and culture from 250,000 to 150,000 years ago. It addresses the fossil, genetic and archaeological evidence and examines the ways these have so far been interpreted, comparing them with parallel developments among Europe's Neanderthals (chapters 2, 7 and 8). The introduction reaffirms the fact that Africa is the cradle of language, mind and culture, and announces the volume as contesting as Eurocentric the prevailing theory that the ‘great leap forward’ for humanity, including its acquisition of language, followed its migration out of Africa, supporting this with archaeological, genetic and other evidence. Using evidence of prehistoric personal ornamentation, together with the archaeology of language and modern cognition, to document historical processes at work in and out of Africa, the authors identify trends in language emergence. According to them, the latest evidence indicates that the choice, transport, colouring and wearing of these ornaments were all part of a form of symbolic behaviour carrying a shared and transmitted meaning. Chapters 3–5 focus on ochre pieces, shell ornaments and collective ritual, and their symbolic meaning, with archaeologists reading into the emergence of these symbolic artefacts a change in behaviour and highlighting the possible links between archaeological findings and language evolution.

In the following chapters, authors rehearse the attempts made to reconstruct the anatomy of the vocal tract using fossil remains, and consider the genetic capacity for language together with the light shed by genes on language evolution. For these authors, Africa is more than the cradle of language: it is its womb, nurturing the embryo as it emerged. They argue in favour of a long-range co-evolution scenario, adding that this hypothesis was confirmed after the conference by the discovery that Neanderthals had shared in the modern human mutations. They question current theories on the Neanderthals, offering a ‘language-free’ explanation for differences between the European Middle and Upper Paleolithic records, based on human energetic needs.

Chapters 10 and 11 – which investigate the possibility of picking up signals of prehistoric events by studying the typology of African languages, adopting perspectives from historical linguistics – conclude that, in spite of limitations, one can trace prehistoric events using areal typology, though they add the caution that African languages do not emerge out of the study as a typologically distinct subgroup. Chapter 11, a very interesting contribution to the book, deals specifically with click languages and what they can or cannot tell us about the origins of language, proving that the use of clicks in paralinguistic utterances are no evidence of their linguistic antiquity.

Chapter 12 considers social aspects of the emergence of language: sharing, exchange and kinship. Chapter 13, again focusing on a single field, considers African hunter-gatherers' cultures as a model for reconstructing the past. The author studies the hunting sounds of Mbendjele Pygmies of northern Congo-Brazzaville and the specific styles of communication they developed for different audiences and situations, mimicking animals – a language combining vocal and visual signs and symbols, and concludes that ‘if hunting, mimicry, faking, and play had a crucial role in the evolution of language’ (p. 256), then hypotheses about the slow emergence of compositional language in human communication would seem to be confirmed. The last chapter focuses less on language and more on subsistence, reproductive and alliance-forming strategies to better understand the emergence of language. In summary, this second book offers again a wide variety of approaches and interpretations, discussing the diversity and multiple sources of human languages, the human genome and human language faculty, and arriving at a broad agreement that there was no single mutation but several, and a process of accelerated change that started long before humankind left Africa.

These companion volumes give an overview of current research in the field while illustrating the diversity of methods, perspectives and approaches adopted; and they propose the building of theories as an essential part of making inferences about language evolution. Beyond the wealth of ideas generated by such a specialized, high-powered multi-disciplinary team, one of the main strengths of the books is its honesty in acknowledging that multi-disciplinary research and investigations on the evolution of language have raised many unanswered questions and posed new challenges for the future. Prominent among these are the need to agree on a definition of language; to find satisfactory ways of testing theories in the absence of direct evidence; and to reconcile conflicting theories on the evolution of language and speech. The collaborating authors are inevitably conscious of the fact that language is an abstraction without archaeological records as such; that there are no solid links between linguistic phenomena and archaeological findings; and that ‘understanding the issue requires intensive interdisciplinary collaboration’ (p. 201). They have therefore set out a research strategy capable of overcoming hindrances and helping investigation to proceed with plausible hypotheses in such fields as anatomy and genetics; and they recognize that the often incompatible ideas presented in these two books will need to be subjected to comparative scrutiny across disciplinary boundaries, with the aim of finding common ground – a tall order.