Language Evolution and Computation Bibliography

The article addresses the issues related to hominins that first embarked upon the language evolutionary trajectory and modality gestural or vocal, used by them. Comparative studies of animal behavior can shed light on these issues provided they follow proper scientific methods. The earliest probable hominin that is well represented in the fossil record, Ardipithecus ramidus (dating to about 4.4 mya), was clearly substantially different from the bonobo, the chimpanzee, or any other primate, at least with respect to locomotor and dental anatomy. Parsimony dictates that any trait present in all descendants of a common ancestor is more likely to have been present in that ancestor than to have evolved separately in each descendant species. In practice, however, a volume of this nature cannot provide an exhaustive survey of the entire animal kingdom. The first article in this section reviews the ape language. It concludes that human-reared and/or trained members of each of the great ape species such as orangutan, chimpanzee, bonobo, and gorilla, have learned to use gestures, tokens, or visual lexigrams. In sum, although non-human primates have often been considered the most intelligent animals, it now appears that many animals are quite smart, and some may rival apes in their language-learning capacities. To date, however, no animal has demonstrated the full range of ape cognitive capacities, and none stands out as a better animal model for language evolution.

This article focuses on the evolution of language along with its anatomy, genetics, and neurology. The concepts of instinct and innateness are actually quite useful for describing behaviors that routinely characterize all members of species or at least all species members of specific sex and age classes. Thus, they tend to be favored by scientists with a primary focus on the distinctive behaviors of individual species. To many developmental biologists and developmental psychologists, however, instinct and innateness are fallacious concepts because all behaviors develop through gene-environment interactions. The solution to this dilemma, in Fitch's view, is to abandon the terms instinct and learning in favor of other terms that more accurately describe the phenomena in question, such as species-specific or species-typical to describe behaviors routinely displayed by all members of a species, and canalization to explain the species-typical gene- environment interactions that produce behavioral regularities. From this perspective, language is a species-specific human behavior that is developmentally canalized via interactions of genes and predictable environmental impacts such as typical adult-infant interactions. In sum, evidence indicates that language evolution probably demanded changes in multiple interacting genes and involved expansions in multiple parts of the brain, as well as changes in the vocal tract and thoracic spinal cord.

This article focuses on the evolution of language over the years. The evidence for primate and human evolution has derived primarily from comparative anatomy and fossil records, although since the 1960s, molecular and biochemical evidences have increasingly been used to delineate phylogenetic relationships among living species and diverse human populations. One of the current research frontiers involves analyses of the DNA of Neanderthals and other fossils. These molecular findings are reviewed by Cann who reports that mitochondrial DNA and the fossil record roughly agree that the phylogenetic split between hominins and panins. It is the earliest possible date for the emergence of protolanguage. Most interpretations of nuclear and mitochondrial DNA suggest that Neanderthal and modern human lineages split somewhere between 270 and 480 thousand years ago (kya), and all modern humans shared a common maternal ancestor in Africa approximately 200 kya. Some mitochondrial DNA data not reviewed by Cann indicates a genetic split between the South African Khoisan peoples and other Africans sometime earlier than 90 kya. The recent nuclear DNA analyses strongly indicate that genetic interchange did occur between modern humans and Neanderthal populations, either directly or indirectly, and, thus, appear to negate completely the strongest versions of the Out-of-Africa model.

The Oxford Handbook of Language Evolution presents critical accounts of every aspect of the field. The book's five parts are devoted to insights from comparative animal behaviour; the biology of language evolution (anatomy, genetics, and neurology); the prehistory of language (when and why did language evolve?); the development of a linguistic species; and language creation, transmission, and change. Research on language evolution has burgeoned over the last three decades. Interdisciplinary activity has produced fundamental advances in the understanding of language evolution and in human and primate evolution more generally. This book presents a wide-ranging summation of work in all the disciplines involved. It highlights the links in different lines of research, shows what has been achieved to date, and considers the most promising directions for future work.

As the title suggests, this work chronicles the evolution of language with special reference to animals. Most organisms communicate with conspecifics, whether intentionally or not, and such communication encompasses all conceivable mechanisms. Vocal and other sound-based signals, such as clicking wings or legs, are common in animals. Visual signals are also widespread, including those associated with humans and other primates: manual and facial signals, and bodily postures. The volume is divided into five parts. Part I, about insights from comparative animal behavior, examines animal communication systems and cognitive capacities of potential relevance to the evolution of language and speech. Part II, which details the biology of language evolution including anatomy, genetics, and neurology, offers various views of the physical components of a language faculty. Part III is about the prehistory of language, and in particular askes: When and why did language evolve? The text presents current interpretations of the selective events that may have led to the evolution of language. Part IV, is on launching language and looks especially at the development of a linguistic species, and it presents articles dealing with central properties to be accounted for in language evolution, and issues surrounding the forces that shaped the language faculty. Finally, the articles in Part V look at language change, creation, and transmission in modern humans, and this part of the book examines a number of putative windows on language evolution; for instance, modern events involving language emergence or change, for which there exists a reasonably concrete evidence, might shed light on the evolution of language itself.

This article deals with the different views of researchers on the central properties to be accounted for in language evolution. Stephen Anderson presents certain structural regularities become established in the world's languages, including universal properties such as structure dependence. Anderson argues that there is no need to assume a dichotomy between a genetically determined language faculty and a language faculty shaped by external factors, such as functional pressures and the effects of grammaticalization. The language faculty supports the learning of specific kinds of linguistic systems, and it would not be at all surprising if natural selection favored those who were able to acquire language most efficiently. Grammars that are most easily learned will be the ones that are acquired, because generations of better learners also shaped grammars to be more learnable. James Hurford, Michael Corballis, Stevan Harnad, Terrence Deacon, and Robbins Burling investigate what cognitive capacities must have evolved before the evolution of any kind of language. These capacities include the development of meaning (semantics and pragmatics), the origins of grounded symbols, and the ability to learn and store words. Hurford argues that other animals possess at least proto-conceptual categories, which form the basis for conceptual meaning. Animals exhibit planning abilities, have mental representations of territory, and can make calculations based on their knowledge, such as transitive inference.

This article discusses the kinds of universal syntactic capacities that prompt many linguists to postulate that syntax is a separate, biologically determined entity. Lexical items are stored in the mental lexicon, an inventory of arbitrary form-meaning associations. These include single words and morphemes smaller than words (such as affixes), multi-word idioms, set phrases, and constructions of various kinds. Vocabulary learning in humans is sophisticated, involving a complex mix of grammatical properties, phonology, semantics, and cultural knowledge. Some aspects are universal, others language-specific. Vocabulary items belong to complex, structured semantic categories. Universally, verbs fit into one or more subcategorization frames, which specify the number and type of obligatory dependents of the verb. The human lexicon displays at least three further unique characteristics. First, the speakers probably store at least 50,000 entries for each of their native languages. Second, though the learning of syntax, phonology, and morphology is subject to critical period effects, new lexical items are learned throughout life and there is no critical period for vocabulary acquisition. Third, the human lexicon crucially contains two major classes of items that include content words, known as lexical categories, and grammatical elements, or functional categories. The lexical/functional division occurs in all languages, including simple languages, such as Riau Indonesian, although functional categories in particular vary greatly cross-linguistically.

This article discusses the emergence of protolanguage. Several researchers suggest that early hominin communication involved some form of pre-language, or protolanguage. Protolanguage is seen as simpler than full language, with a proto-lexicon. Protolanguage may have utilized vocal, gestural, and mimed components. A compositional or lexical protolanguage consists of single protowords, initially uttered separately and slowly, and subsequently joined in short, fairly random sequences. It has no hierarchical structure, no syntactic combinatorial principles, and only a loose pragmatic relationship between protowords. Protolanguage exhibits several properties. One of the properties is that the ordering of elements is relatively random. No hierarchical syntactic structure constrains surface order, and different word orders have no link to information structure. Ancestral protolanguage putatively contained various purely semantically based principle that map into linear adjacency without using anything syntactic. Ancestral protolanguage putatively lacked a mechanism for assembling words into structural units. The protolanguage lacks a distinction between lexical elements primarily verbs, nouns, adjectives and functional elements such as grammatical items, including determiners, auxiliaries, and sub- words. Modern protolanguages lack grammatical markers, while in full languages, functional and lexical elements occur in roughly equal proportions in utterances. The transition to language involved the gradual accretion of other word classes via the same processes of grammaticalization that occur in all recorded languages.

This article covers the processes of (modern) language creation and change, and the roles played in language evolution by socio/cultural transmission. Bernd Heine and Tania Kuteva report on the uses of well-known processes at work in observable language change to reconstruct a plausible scenario for the development of the earliest languages. Joan Bybee reports on the concept of grammaticalization that refers to a bundle of processes causing diachronic change that are known to occur in all languages. Grammaticalization is posited as a critical driving force in the evolution of language, and grammaticalization theory gives us a scientific tool for reconstructing earlier linguistic states. Paul Roberge argues against the prevailing view concerning the role of child learners in language change in connection with the formation of creoles. He argues that native acquisition of pidgins is not necessary to form creoles, which are full linguistic systems. Roberge compares the factors leading to the evolution of full language from protolanguage with the factors involved in the formation of pidgins and creoles. Susan Goldin-Meadow reports on the theme of language creation. She explores the role of the manual modality when used alongside speech, and then investigates what changes occur when this modality fulfils all the functions of language, without speech. Sign languages are fully- fledged languages, but more primitive gestural communication occurs in homesign systems.

Evans \& Levinson (2009) argue that language diversity is more robust than linguistic homogeneity, and also suggest that explanations for recurring patterns in language are not the product of an innate, evolved language faculty. I examine various kinds of evidence in favour of a specialized language faculty, and argue against the claim that typologically distinct languages must have distinct parsing systems.

Christiansen & Chater (C&C) suggest that language is itself an evolutionary system, and that natural languages to be easy to learn and process. The tight economy of the world's case-marking systems lends support to this hypothesis. Only two major case systems occur, cross-linguistically, and noun phrases are seldom overtly case-marked wherever zero-marking would be functionally practical.

Language is typically argued (or assumed) to be an adaptive trait in the Homo lineage, and various specific selection pressures are offered to explain why language would have increased fitness in a population. However, it is incoherent to discuss language as a monolithic entity: the set of properties that comprise the full, complex language faculty almost certainly evolved independently, and any pressure that buys one of these properties does not necessarily entail the others. Some recent work on kin selection starts by discussing the evolution of speech, but then moves on to the selective value of the exchange of information without indicating how our ancestors got from vocalization to propositions. This is too large a leap, and more specific mechanisms must be proposed if the hypotheses are to be seriously considered.

This paper challenges recent assumptions that holophrastic utterances could be planned, processed, stored and retrieved from storage, focussing on three specific issues: (i) Problems in conceptual planning of multi-proposition utterances of the type proposed by Arbib (2005), Mithen (2005); (ii) The question of whether holophrastic protolanguage could have been processed by a special holistic mode, the precursor to a projected idiom mode in modern language; (iii) The implications for learning a holophrastic proto-lexicon in light of lexical constraints on word learning. Modern speakers only plan utterances in clause-sized units, and it is improbable that protolanguage speakers had more complex abilities. Moreover, the production and comprehension of idioms sheds no light on a putative holistic mode of language processing, since idioms are not processed in this way. Finally, innate constraints on learning lexical items preclude the types of word meanings proposed by proponents of holophrastic protolanguage.

The dominant theory of the evolution of complex language from protolanguage can be termed the synthetic approach. Under this view, single words arose first in evolution, and were combined as syntax evolved. More recently, an alternative scenario for protolanguage has been proposed, which we can term the holistic approach. Scholars subscribing to this view propose that words emerge from longer, entirely arbitrary strings of sounds - non-compositional utterances - via a process of fractionation. Such holistic utterances initially have no internal structure, but represent whole messages. The idea is that over time, chance phonetic similarities are observed between sections of utterances, and that if similar meanings can be ascribed to these strings, then 'words' will emerge. This paper dissects the main ideas found in the holistic approach, and argues on a number of grounds that it is conceptually and empirically flawed. A proposal that protolanguage developed out of an earlier holistic primate communication system is hard to sustain, in view of differences between primate vocalization and language. Evidence against the holistic approach is offered on the basis of known facts about the historical development of natural languages, and a conclusion is drawn in favour of synthetic models of protolanguage.