Many animals, including dogs, produce vocal signals in which their mouths open and close producing In contrast, the vocal signals of species other than humans are tied to emotional states. The Broca's-Wernicke's area model of the brain bases of language is wrong.

Two computer simulations are investigated that model interaction of cultural evolution of language and biological evolution of adaptations to language. Both are agent‐based models in which a population of agents imitates each other using realistic vowels. The agents evolve under selective pressure for good imitation. In one model, the evolution of the vocal tract is modeled; in the other, a cognitive mechanism for perceiving speech accurately is modeled. In both cases, biological adaptations to using and learning (...) speech evolve, even though the system of speech sounds itself changes at a more rapid time scale than biological evolution. However, the fact that the available acoustic space is used maximally (a self‐organized result of cultural evolution) is constant, and therefore biological evolution does have a stable target. This work shows that when cultural and biological traits are continuous, their co‐evolution may lead to cognitive adaptations that are strong enough to detect empirically. (shrink)

Two computer simulations are investigated that model interaction of cultural evolution of language and biological evolution of adaptations to language. Both are agent-based models in which a population of agents imitates each other using realistic vowels. The agents evolve under selective pressure for good imitation. In one model, the evolution of the vocal tract is modeled; in the other, a cognitive mechanism for perceiving speech accurately is modeled. In both cases, biological adaptations to using and learning (...) speech evolve, even though the system of speech sounds itself changes at a more rapid time scale than biological evolution. However, the fact that the available acoustic space is used maximally is constant, and therefore biological evolution does have a stable target. This work shows that when cultural and biological traits are continuous, their co-evolution may lead to cognitive adaptations that are strong enough to detect empirically. (shrink)

Leading scholars draw on the latest research to explore what birdsong can tell us about the biology of human speech and language and the consequences for evolutionary biology.

Scholars have long been captivated by the parallels between birdsong and human speech and language. In this book, leading scholars draw on the latest research to explore what birdsong can tell us about the biology of human speech and language and the consequences for evolutionary biology. They examine the cognitive and neural similarities between birdsong learning and speech and language acquisition, considering vocal imitation, auditory learning, an early vocalization phase, the structural properties of birdsong and human language, (...) and the striking similarities between the neural organization of learning and vocal production in birdsong and human speech. After outlining the basic issues involved in the study of both language and evolution, the contributors compare birdsong and language in terms of acquisition, recursion, and core structural properties, and then examine the neurobiology of song and speech, genomic factors, and the emergence and evolution of language. Contributors: Hermann Ackermann, Gabriël J.L. Beckers, Robert C. Berwick, Johan J. Bolhuis, Noam Chomsky, Frank Eisner, Martin Everaert, Michale S. Fee, Olga Fehér, Simon E. Fisher, W. Tecumseh Fitch, Jonathan B. Fritz, Sharon M.H. Gobes, Riny Huijbregts, Eric Jarvis, Robert Lachlan, Ann Law, Michael A. Long, Gary F. Marcus, Carolyn McGettigan, Daniel Mietchen, Richard Mooney, Sanne Moorman, Kazuo Okanoya, Christophe Pallier, Irene M. Pepperberg, Jonathan F. Prather, Franck Ramus, Eric Reuland, Constance Scharff, Sophie K. Scott, Neil Smith, Ofer Tchernichovski, Carel ten Cate, Christopher K. Thompson, Frank Wijnen, Moira Yip, Wolfram Ziegler, Willem Zuidema. (shrink)

A textbook for third year undergraduates and postgraduates. In a challenging philosophic investigation of the origin of consciousness and human culture, Dewart (religion, emeritus, U. of Toronto) proposes a theory to explain the origin of all specifically human traits. Complementing the theory of evolution through natural selection, it explains the emergence and those the continuing evolution of characterstics through the interaction of experience and speech. Annotation copyrighted by Book News, Inc., Portland, OR.

The species-specific organizational property of speech is a continual mouth open-close alternation, the two phases of which are subject to continual articulatory modulation. The cycle constitutes the syllable, and the open and closed phases are segments framescontent displays that are prominent in many nonhuman primates. The new role of Broca's area and its surround in human vocal communication may have derived from its evolutionary history as the main cortical center for the control of ingestive processes. The frame and content (...) components of speech may have subsequently evolved separate realizations within two general purpose primate motor control systems: (1) a motivation-related medial system, including anterior cingulate cortex and the supplementary motor area, for self-generated behavior, formerly responsible for ancestral vocalization control and now also responsible for frames, and (2) a lateral system, including Broca's area and surround, and Wernicke's area, specialized for response to external input (and therefore the emergent vocal learning capacity) and more responsible for content. (shrink)

Inferences made from endocasts of fossil skulls cannot provide information on the function of particular neocortical areas or the subcortical pathways to prefrontal cortex that form part of the neural substrate for speech, syntax, and certain aspects of cognition. The neural bases of syntax cannot be disassociated from “communication.” Manual motor control was probably a preadaptive factor in the evolution of humansyntactic ability, but neurophysiological data on living humans show that speech motor control and syntax are more (...) closely linked. The evolution of fully modern speech occurred fairly recently; thoughHomo habilismay have had some degree of speech and syntactic ability, it was not fully modern. Stone tools are uncertain indices of language or cognition. (shrink)

The sound system of a language must be able to support a perceptual contrast between different words in order to signal communicatively relevant meaning distinctions. In this paper, we use a simple agent-based exemplar model in which the evolution of sound-category systems is understood as a co-evolutionary process, where the range of variation within sound categories is constrained by functional pressure to keep different words perceptually distinct. We show that this model can reproduce several observed effects on the range (...) of sound variation. We argue that phonological systems can be seen as finding a relative optimum of variation: Efficient communication is sustained while at the same time, hidden category variation provides pathways for future evolution. (shrink)

We consider Sussman et al. 's suggestion that auditory biases for processing low-noise relationships among pairs of acoustic variables is a preadaptation for human speech processing. Data from other animal communication systems, especially those involving sexual selection, also suggest that neural biases in the receiver system can generate strong selection on the form of communication signals.

The target article by Christiansen & Chater (C&C) offers an integrated framework for the study of language acquisition and, possibly, a novel role for internal speech in language acquisition. However, the “Now-or-Never bottleneck” raises a paradox for language evolution. It seems to imply that language complexity has been either reduced over time or has remained the same. How, then, could languages as complex as ours have evolved in prelinguistic ancestors? Linguistic Platonism could offer a solution to this paradox.

Recently theorists have developed competing accounts of the origins and nature of protolanguage and the subsequent evolution of language. Debate over these accounts is lively. Participants ask: Is music a direct precursor of language? Were the first languages gestural? Or is language continuous with primate vocalizations, such as the alarm calls of vervets? In this article I survey the leading hypotheses and lines of evidence, favouring a largely gestural conception of protolanguage. However, the “sticking point” of gestural accounts, to (...) use Robbins Burling’s phrase, is the need to explain how language shifted to a largely vocal medium. So with a critical eye I consider Michael Corballis’s most recent expression of his ideas about this transition. Corballis’s view is an excellent foil to mine and I present it as such. Contrary to Corballis’s account, and developing Burling’s conjecture that musicality played some role, I argue that the foundations of an evolving musicality provided the means and medium for the shift from gestural to vocal dominance in language. In other words, I suggest that an independently evolving musicality prepared ancient hominins, morphologically and cognitively, for intentional articulate vocal production, enabling the evolution of speech. (shrink)

The strong predominance of right-handedness appears to be a uniquely human characteristic, whereas the left-cerebral dominance for vocalization occurs in many species, including frogs, birds, and mammals. Right-handedness may have arisen because of an association between manual gestures and vocalization in the evolution of language. I argue that language evolved from manual gestures, gradually incorporating vocal elements. The transition may be traced through changes in the function of Broca's area. Its homologue in monkeys has nothing to do with vocal (...) control, but contains the so-called “mirror neurons,” the code for both the production of manual reaching movements and the perception of the same movements performed by others. This system is bilateral in monkeys, but predominantly left-hemispheric in humans, and in humans is involved with vocalization as well as manual actions. There is evidence that Broca's area is enlarged on the left side in Homo habilis, suggesting that a link between gesture and vocalization may go back at least two million years, although other evidence suggests that speech may not have become fully autonomous until Homo sapiens appeared some 170,000 years ago, or perhaps even later. The removal of manual gesture as a necessary component of language may explain the rapid advance of technology, allowing late migrations of Homo sapiens from Africa to replace all other hominids in other parts of the world, including the Neanderthals in Europe and Homo erectus in Asia. Nevertheless, the long association of vocalization with manual gesture left us a legacy of right-handedness. Key Words: cerebral dominance; gestures; handedness; hominids; language evolution; primates; speech; vocalization. (shrink)

While influential works since the 1970s have widely assumed that imitation is an innate skill in both human and non-human primate neonates, recent empirical studies and meta-analyses have challenged this view, indicating other forms of reward-based learning as relevant factors in the development of social behavior. The visual input translation into matching motor output that underlies imitation abilities instead seems to develop along with social interactions and sensorimotor experience during infancy and childhood. Recently, a new visual stream has been identified (...) in both human and non-human primate brains, updating the dual visual stream model. This third pathway is thought to be specialized for dynamics aspects of social perceptions such as eye-gaze, facial expression and crucially for audio-visual integration of speech. Here, we review empirical studies addressing an understudied but crucial aspect of speech and communication, namely the processing of visual orofacial cues and its integration with vocal auditory cues. Along this review, we offer new insights from our understanding of speech as the product of evolution and development of a rhythmic and multimodal organization of sensorimotor brain networks, supporting volitional motor control of the upper vocal tract and audio-visual voices-faces integration. (shrink)

This paper describes the evolution of the family role face – specifically, the roles of father, mother and child – in a concrete period of the Spanish social history -from the end of 19th century to the 1960s. To achieve this goal, a corpus of theater plays is analyzed from a functional and pragmalinguistic perspective in a socio-historical context. The focus is on the quantitative and qualitative analysis of the projection of role face in the expression of directive (...) class='Hi'>speech acts and their possible modulation through two pragmatic strategies: mitigation and intensification. Based on the results of the analysis, a sociopragmatic interpretation is carried out by identifying the connection between the choice of pragmalinguistic strategies and the need of the speakers’ autonomy face and affiliation face in different roles as family member in the given period. The results point to a progressive solidarity in father-child relationships during this period. On the one hand, that is based on the erosion of the authoritarian component of parental roles. On the other hand, it is anchored in the consolidation of proximity, closeness (‘confianza’) and affectivity. From a methodological point of view, the present study confirms the possibility of characterizing a sociopragmatic aspect (role face) on the basis of pragmalinguistic elements, i.e. the linguistic expression of directive speech acts, and its modulation through mitigation and intensification. (shrink)

The Frame/Content theory deals with how and why the first language evolved the present-day speech mode of programming syllable “Frame” structures with segmental “Content” elements. The first words are considered, for biomechanical reasons, to have had the simple syllable frame structures of pre-speech babbling, and were perhaps parental terms, generated within the parent–infant dyad. Although all gestural origins theories have iconicity as a plausible alternative hypothesis for the origin of the meaning-signal link for words, they all share the (...) problems of how and why a fully fledged sign language, necessarily involving a structured phonology, changed to a spoken language. (shrink)

For many years the evolution of language has been seen as a disreputable topic, mired in fanciful “just so stories” about language origins. However, in the last decade a new synthesis of modern linguistics, cognitive neuroscience and neo-Darwinian evolutionary theory has begun to make important contributions to our understanding of the biology and evolution of language. I review some of this recent progress, focusing on the value of the comparative method, which uses data from animal species to draw (...) inferences about language evolution. Discussing speech first, I show how data concerning a wide variety of species, from monkeys to birds, can increase our understanding of the anatomical and neural mechanisms underlying human spoken language, and how bird and whale song provide insights into the ultimate evolutionary function of language. I discuss the “descended larynx” of humans, a peculiar adaptation for speech that has received much attention in the past, which despite earlier claims is not uniquely human. Then I will turn to the neural mechanisms underlying spoken language, pointing out the difficulties animals apparently experience in perceiving hierarchical structure in sounds, and stressing the importance of vocal imitation in the evolution of a spoken language. Turning to ultimate function, I suggest that communication among kin (especially between parents and offspring) played a crucial but neglected role in driving language evolution. Finally, I briefly discuss phylogeny, discussing hypotheses that offer plausible routes to human language from a non-linguistic chimp-like ancestor. I conclude that comparative data from living animals will be key to developing a richer, more interdisciplinary understanding of our most distinctively human trait: language. (shrink)

Infants' own activities create and actively select their learning experiences. Here we review recent models of embodied information seeking and curiosity-driven learning and show that these mechanisms have deep implications for development and evolution. We discuss how these mechanisms yield self-organized epigenesis with emergent ordered behavioral and cognitive developmental stages. We describe a robotic experiment that explored the hypothesis that progress in learning, in and for itself, generates intrinsic rewards: The robot learners probabilistically selected experiences according to their potential (...) for reducing uncertainty. In these experiments, curiosity-driven learning led the robot learner to successively discover object affordances and vocal interaction with its peers. We explain how a learning curriculum adapted to the current constraints of the learning system automatically formed, constraining learning and shaping the developmental trajectory. The observed trajectories in the robot experiment share many properties with those in infant development, including a mixture of regularities and diversities in the developmental patterns. Finally, we argue that such emergent developmental structures can guide and constrain evolution, in particular with regard to the origins of language. (shrink)

Charmed by Corballis's presentation, we challenge the use of mirror neurons as a supporting platform for the gestural theory of language, the link between vocalization and cerebral specialization, and the relationship between gesture and language as two separate albeit coupled systems of communication. We revive an alternative explanation of lateralization of language and handedness.

A perception-action system may underlie the mechanisms by which human speech exchange in social interaction is managed, as well as the evolutionary precursors of these mechanisms in closely related species. Some phenomena of interaction well-studied by sociologists are suggested as a point of departure for further research.

Much of the material MacNeilage cites to support his frame/content theory for the evolution of speech production in humans is not unique to mammals. Parallels can be drawn for comparable evolution of vocal flexibility (specifically the reproduction of human speech) in birds. I describe several such parallels and conclude that MacNeilage's hypotheses may have broader application than he envisioned.

Temporal regularities in speech, such as interdependencies in the timing of speech events, are thought to scaffold early acquisition of the building blocks in speech. By providing on-line clues to the location and duration of upcoming syllables, temporal structure may aid segmentation and clustering of continuous speech into separable units. This hypothesis tacitly assumes that learners exploit predictability in the temporal structure of speech. Existing measures of speech timing tend to focus on first-order regularities (...) among adjacent units, and are overly sensitive to idiosyncrasies in the data they describe. Here, we compare several statistical methods on a sample of 18 languages, testing whether syllable occurrence is predictable over time. Rather than looking for differences between languages, we aim to find across languages (using clearly defined acoustic, rather than orthographic, measures), temporal predictability in the speech signal which could be exploited by a language learner. First, we analyse distributional regularities using two novel techniques: a Bayesian ideal learner analysis, and a simple distributional measure. Second, we model higher-order temporal structure—regularities arising in an ordered series of syllable timings—testing the hypothesis that non-adjacent temporal structures may explain the gap between subjectively-perceived temporal regularities, and the absence of universally-accepted lower-order objective measures. Together, our analyses provide limited evidence for predictability at different time scales, though higher-order predictability is difficult to reliably infer. We conclude that temporal predictability in speech may well arise from a combination of individually weak perceptual cues at multiple structural levels, but is challenging to pinpoint. (shrink)

Our understanding of language, its origins and subsequent evolution, is shaped not only by data and theories from the language sciences, but also fundamentally by the biological sciences. Recent developments in genetics and evolutionary theory offer both very strong constraints on what scenarios of language evolution are possible and probable, but also offer exciting opportunities for understanding otherwise puzzling phenomena. Due to the intrinsic breathtaking rate of advancement in these fields, and the complexity, subtlety, and sometimes apparent non-intuitiveness (...) of the phenomena discovered, some of these recent developments have either being completely missed by language scientists or misperceived and misrepresented. In this short paper, we offer an update on some of these findings and theoretical developments through a selection of illustrative examples and discussions that cast new light on current debates in the language sciences. The main message of our paper is that life is much more complex and nuanced than anybody could have predicted even a few decades ago, and that we need to be flexible in our theorizing instead of embracing a priori dogmas and trying to patch paradigms that are no longer satisfactory. (shrink)

We agree with MacNeilage's claim that speech stems from a volitional vocalization pathway between the cingulate and the supplementary motor area (SMA). We add the vocal self- monitoring system as the first recruitment of the Broca-Wernicke circuit. SMA control for “frames” is supported by wrong consonant-vowel recurring utterance aphasia and an imaging study of quasi-reiterant speech. The role of Broca's area is questioned in the emergence of “content,” because a primary motor mapping, embodying peripheral constraints, seems sufficient. Finally, (...) we reject a uniquely peripheral account of speech emergence. (shrink)

There is evidence of reciprocal connectivity, similarity of oscillatory responses to stimulation of multiple motor and somatosensory cortices, whole system oscillation, and short- latency responses to behavioral perturbation. These suggest that frame/content may be instantiated by overlapping neural populations, and that the genesis of frame oscillations may be profitably thought of as an emergent property of a distributed neural system.

This paper and its subsequent parts (Part II and Part III) build on an earlier publication (McKenna 1986). They suggest that important clinical data on the relationship between infantile constitutional deficits and microenvironmental factors relevant to SIDS can be acquired by examining the physiological regulatory effects (well documented among nonhuman primates) that parents assert on their infants when they sleep together.I attempt to show why access to parental sensory cues (movement, touch, smell, sound) that induce arousals in infants while they (...) sleep could possibly help one of many different subclasses of infants either to override certain kinds of sleep-induced breathing control errors suspected to be involved in SIDS or to avoid them altogether. I do not suggest that solitary nocturnal sleep “causes” SIDS, that all parents should sleep with their infants, or that traditional SIDS research strategies should be abandoned. However, using evolutionary data, I do suggest that an adaptive fit exists between parent-infant sleep contact and the natural physiological vulnerabilities of the neurologically immature human infant, whose breathing system is more complex than that of other mammals owing to its speech-breathing abilities. This “fit” is best understood, it is argued, in terms of the 4–5 million years of human evolution in which parent-infant contact was almost certainly continuous during at least the first year of an infant’s life. Thus, to dismiss the idea that solitary sleep has no physiological consequences for infants does not accord with scientific facts. (shrink)

Guided by neuroscience, animal behavior, evolution, philosophy, and psychology, Asma burrows deep into the human psyche to look right at the enigmatic but powerful engine that is our improvisational creativity—the source, he argues, of our remarkable imaginational capacity. How is it, he asks, that a story can evoke a whole world inside of us? How are we able to rehearse a skill, a speech, or even an entire scenario simply by thinking about it? How does creativity go beyond (...) experience and help us make something completely new? And how does our moral imagination help us sculpt a better society? As he shows, we live in a world that is only partly happening in reality. Huge swaths of our cognitive experiences are made up by “what-ifs,” “almosts,” and “maybes,” an imagined terrain that churns out one of the most overlooked but necessary resources for our flourishing: possibilities. Considering everything from how imagination works in our physical bodies to the ways we make images, from the mechanics of language and our ability to tell stories to the creative composition of self-consciousness, Asma expands our personal and day-to-day forms of imagination into a grand scale: as one of the decisive evolutionary forces that has guided human development from the Paleolithic era to today. The result is an inspiring look at the rich relationships among improvisation, imagination, and culture, and a privileged glimpse into the unique nature of our evolved minds. (shrink)

This article explores the evolution of Article 17 of the European Convention on Human Rights from its inception as a safeguard against totalitarian regimes to its contemporary application in the suppression of hate speech. The formulation of key issues around the paper’s discussion is prompted by the 2023 case of _Lenis v Greece_ where the European Court of Human Rights extended the use of Article 17 to homophobic speech. Despite originating from the historical context of post-World War (...) II atrocities, the application of Article 17 has extended beyond its original intent, raising concerns about its compatibility with democratic principles and its potential to undermine freedom of expression. Through a comprehensive analysis of relevant case law and scholarly discourse, this paper examines the tension between Article 17 and Article 10 of the ECHR, which guarantees the right to freedom of expression. It argues that the broad interpretation and extensive utilization of Article 17 pose significant threats to democracy and exacerbate challenges faced by marginalized communities. Drawing parallels with the United Nations Human Rights Committee’s approach to abuse clauses, the paper advocates for a more cautious and judicious application of Article 17 to strike a balance between protecting vulnerable groups and upholding fundamental freedoms in a liberal democracy. (shrink)

In this important volume Habermas outlines the views which form the basis of his critical theory of modern societies. The volume comprises five interlocking essays, which together define the contours of his theory of communication and of his substantive account of social change. ′What is Universal Pragmatics?′ is the best available statement of Habermas′s programme for a theoryof communication based on the analysis of speech acts. In the following two essays Habermas draws on the work of Kohlberg and others (...) to develop a distinctive account of moral consciousness and normative structures. ′Toward a Reconstruction of historical Materialsim′ takes these issues further, offering a wide–ranging reconstruction of Marx′s historical materialsim understood as a theory of social evolution. The final essay focuses on the question of legitimacy and on the legitimation problems faced by modern states. This book is essential reading for anyone concerned with the key questions of social and political theory today. (shrink)

This book explores the evolution of the mental competence for self-reflection: why it evolved, under what selection pressures, in what environments, out of what precursors, and with what mental resources. Integrating evolutionary, psychological, and philosophical perspectives, Radu J. Bogdan argues that the competence for self-reflection, uniquely human and initially autobiographical, evolved under strong and persistent sociocultural and political pressures on the developing minds of older children and later adults. Self-reflection originated in a basic propensity of the human brain to (...) rehearse anticipatively mental states, speech acts, actions, and states of the world in order to service one's elaborate goal policies. These goal policies integrate offline representations of one's own mental states and actions and those of others in order to handle the challenges of a complex and dynamic sociopolitical and sociocultural life, calling for an adaptive intramental self-regulation: that intramental adaptation is self-reflection. (shrink)

An awareness of the significance of location in the production and dissemination of scientific knowledge has brought a new dimension to recent work on the sociology of science. But the importance of speech in scientific enterprises has been less well developed. This article explores the idea of `spaces of speech' by underscoring the connections between location and locution. It develops a case study of how Darwinian evolution was talked about in different sites using examples from Ireland and (...) the American South during the latter part of the 19th century. These reveal how sites enable and constrain what may be said, and heard, about particular scientific claims, and how they are crucial to understanding the circulation of scientific claims in public arenas. (shrink)

The First Amendment to the US Constitution protects commercial speech from government interference. Commercial speech has been defined by the US Supreme Court as speech that proposes a commercial transaction, such as marketing and labeling. Companies that produce products associated with public health harms, such as alcohol, tobacco, and food, thus have a constitutional right to market these products to consumers. This article will examine the evolution of US law related to the protection of commercial (...) class='Hi'>speech, often at the expense of public health. It will then identify outstanding questions related to the commercial speech doctrine and the few remaining avenues available in the United States to regulate commercial speech including the use of government speech and addressing deceptive and misleading commercial speech. (shrink)

Evolutionary developmental systems theory stresses that selection pressures operate on entire developmental systems rather than just genes. This study extends this approach to language evolution, arguing that selection pressure may operate on two quasi-independent timescales. First, children clearly must acquire language successfully and evolution must equip them with the tools to do so. Second, while this is developing, they must also communicate with others in the moment using partially developed knowledge. These pressures may require different solutions, and their (...) combination may underlie the evolution of complex mechanisms for language development and processing. I present two case studies to illustrate how the demands of both real-time communication and language acquisition may be subtly different. The first case study examines infant-directed speech. A recent view is that IDS underwent cultural to statistical learning mechanisms that infants use to acquire the speech categories of their language. However, recent data suggest is it may not have evolved to enhance development, but rather to serve a more real-time communicative function. The second case study examines the argument for seemingly specialized mechanisms for learning word meanings. Both behavioral and computational work suggest that learning may be much slower and served by general-purpose mechanisms like associative learning. Fast-mapping, then, may be a real-time process meant to serve immediate communication, not learning, by augmenting incomplete vocabulary knowledge with constraints from the current context. Together, these studies suggest that evolutionary accounts consider selection pressure arising from both real-time communicative demands and from the need for accurate language development. (shrink)

How music and speech evolved is a mystery. Several hypotheses on their origins, including one on their joint origins, have been put forward but rarely tested. Here we report and comment on the first experiment testing the hypothesis that speech and music bifurcated from a common system. We highlight strengths of the reported experiment, point out its relatedness to animal work, and suggest three alternative interpretations of its results. We conclude by sketching a future empirical programme extending this (...) work. (shrink)

Inner speech emerges in early childhood, in parallel with the maturation of the dorsal language stream. To date, the developmental relations between these two processes have not been examined. We review evidence that the dorsal language stream has a role in supporting the psychological phenomenon of inner speech, before considering paediatric studies of the dorsal stream’s anatomical development and evidence for its emerging functional roles. We examine possible causal accounts of the relations between these two developmental processes, and (...) consider their implications for phylogenetic theories about the evolution of inner speech and the accounts of the ontogenetic relations between language and cognition. (shrink)

The first major advances in the understanding of the neurological bases for language abilities were the results of the study of the brains and behaviors of patients with language impairments due to focal brain damage. The two most prominent pioneers in this field are remembered because their names have become associated with distinctive aphasia (language loss) syndromes and the brain regions associated with them. In 1861 Paul Broca described the damage site in the brain of a patient who had lost (...) the ability to produce articulate speech as a result of a stroke. Broca's aphasia, as it is now commonly called, is produced by damage that involves the inferior left frontal lobe of the brain. It tends to produce both a loss of articulatory skill (sometimes but not always with paralysis) and (as discovered much later) problems with grammar and syntax, including grammatical comprehension under certain conditions. Despite speech production impairments, Broca's aphasics do not have basic word‐ and sentence‐comprehension difficulties, when comprehension is not dependent on syntactic analysis. In 1874 Carl Wernicke demonstrated that damage to the left superior temporal lobe produced a different syndrome of language impairments. Wernicke's aphasia generally spares fluent, syntactic speech but impairs the use and comprehension of content words. Wernicke's aphasics'speech includes inappropriate word substitutions, neologisms, and semantic confusions, and their comprehension is similarly disturbed. These early studies also demonstrated that these aphasic disturbances were almost exclusively associated with damage to the structures of the left cerebral hemisphere, even though anatomically corresponding structures are present on both sides of the brain. However, this is not true of all language functions. Some left‐handed individuals can suffer aphasia from right hemisphere damage, and recent studies of patients with right hemisphere damage without aphasia have demonstrated impairment of their comprehension above the sentence level (e.g., interpretation of jokes and stories) and in the production and interpretation of prosodic features of speech (rhythmic and tonal patterning that conveys emphasis and emotion). (shrink)