LINGUIST List 11.1317

Wed Jun 14 2000

Review: Oller: The Emergence of the speech capacity

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  • Madalena Cruz-Ferreira, Book review

    Message 1: Book review

    Date: Thu, 1 Jun 2000 13:53:08 +0800
    From: Madalena Cruz-Ferreira <mcfpacific.net.sg>
    Subject: Book review


    Oller, D. Kimbrough (2000), The emergence of the speech capacity, Lawrence Erlbaum Associates, Mahwah, NJ. xvii + 428 pages, paperback edition US$39.95.

    Reviewed by Madalena Cruz-Ferreira, National University of Singapore.

    Synopsis

    Kimbrough Oller's book presents a model accounting for the emergence of the speech capacity in human infants and in the human species. The model consists of a hierarchical system of properties that characterise potential communication systems at a deep level of abstraction, the infrastructural level.

    Chapter 1 introduces the theoretical framework, as well as the key concerns and goals of the book, with preliminary discussion. The framework of infraphonology, expanded from Oller's earlier research, involves the assessment of "the infrastructure of human speech sounds" (p.10), specifying the properties accounting for well-formed elements of phonology. The syllable is taken as the crucial unit in the model, and is defined as the minimal rhythmic unit of natural phonological systems.

    Chapter 2 gives the historical background to the model adopted in the book, arguing that infant vocal development cannot be understood from the perspective of a mature linguistic system. Oller views the shoe-horning (his term) of precanonical infant vocalisations into the "operational-level categories" (p.29) of mature speech as deeply misleading and as the prime factor behind much confusion in the study of speech development. Crucially, transcription systems devised for adult systems are inadequate in grasping stages of development, in that phonetic transcription presumes well-formedness in early infant vocalisations where, Oller argues, none is to be found. The chapter reviews Jakobson's, Lenneberg's and Irwin's approaches to speech development, pointing out what stands out as erroneous claims due to inappropriate methodology and research tools.

    Chapter 3 argues for an infrastructural approach to infant speech, through which the stages of vocal development in the first few months of life become apparent, in that each stage is typified by the production of particular protophones. These are "untranscribable categories" (p.50) that constitute the key bridge to full-blown speech, and include "all the utterance types that appear to be precursors to speech" (p.10).

    Chapter 4 lays out the basic tenets of infraphonology. Four basic stages in vocal development are set up, each defined by typical protophone production and each evidencing progressive infraphonological achievement, as follows: In Stage 1, the Phonation stage (0-2 months), the infant produces quasivowels, achieving normal phonation. Quasivowels are sounds that "lack full vocalic status" because they are produced "with the vocal tract at rest" (p.63). In Stage 2, Primitive Articulation (1-4 months), the infant produces gooing, achieving limited articulation. In Stage 3, Expansion (3-8 months), the infant produces full vowels as well as marginal babbling, achieving full resonance/articulation. In Stage 4, the Canonical stage (5-10 months), the infant produces canonical babbling, achieving well-timed articulation. Precanonical and canonical babbling constitute two distinct stages, the onset of the latter established when infants "produce closure and opening sequences with normal phonation in well-timed, often repetitive patterns" (p.65), including reduplicated sequences. Canonical syllable formation obeys four basic principles: Normal phonation: smooth voicing Articulation: movement of the vocal tract during voicing Full resonance: opening and posturing of the tract during vowel-like sounds Rapid transitions: well-timed movements from closed to open postures.

    Chapter 5 starts by assessing the heuristic power of infrastructural models in other research domains, namely, chemistry and biology. Oller argues that infrastructural models may well be universal and, as "conditions of the universe", they are of course "independent of humanity" (p. 105). Vocal development, organised by infraphonological theory, follows a natural logic on the path leading from primitive capabilities to the structured patterns present in mature speech. There follows a characterisation of speech sounds, from the range of all human articulatory possibilities, in order to establish the conditions that define "possible speech event types" (p.86). Instrumental analysis is called for in this quest, but Oller rightly emphasises the crucial role played by human listeners, the "real perceivers" (p.89), in their judgement of relevant speech principles and categories, by which instrumental quantification should be guided. A universal characterisation of the syllable is proposed, with the proviso that infraphonology must ultimately "specify the contrastive sounds at each of the tiers of human phonological function" (p.81), like, for example, phonological features, segments, feet, phrases and higher order rhythmic units. The chapter closes with the statement of infraphonology as a part of Universal Grammar, independent from emergentist or nativist claims on grammatical principles.

    Chapter 6 discusses vocal and gestural development within the general context of motor development, highlighting the role of motor practice in vocal development. The concept of canalisation is analysed, concerning developmental events that are difficult to "deflect from a biologically preordained course" (p.113). Vocal and signed babbling constitute examples of canalised behaviour in hearing and deaf infants, respectively, as does for example, hand banging and motor engagement in other rhythmical patterns in all infants. The role of auditory experience appears as non-negligible for the emergence of vocal babbling, as differences in its timing onset are discernible between hearing and deaf infants.

    Chapter 7 investigates key stages in vocal development, in particular the babbling stage, in the light of several studies targeting infants in conditions of socio-economic deprivation, premature birth or bilingualism, or a combination of these. Results confirm the robustness of these stages, suggesting that the logical growth of the infraphonological capabilities is immutably embedded in our biological makeup.

    In the light of this evidence, Chapter 8 examines the limits on the disruption of the canalised pattern of babbling, from case studies on profound deafness and mental retardation. These studies show that protophone development may be delayed or otherwise disrupted, but not prevented, and that disruption in the timing onset of canonical babbling occurs in infants who later show deviant development of language-related abilities. This clear correlation encourages the generalisation of diagnostic procedures whereby 10-month old infants may be screened for hearing impairment, or other impairment, on the basis of an evaluation of canonical babbling onset.

    Chapter 9 turns to the social function of infant vocal communication, ranging from vegetative sounds to protophones. It describes the ways in which infants seek mastery of the powerful human vocal tool through exploration of its flexibility along several dimensions that infants isolate for the purpose of practice. For example, the alternations of whispers and yells explore the parameter of intensity. Body posture and facial expressions, of the child as well as of interfacing adults, gradually acquire social significance too.

    Chapter 10 sets out to investigate the specificity of protophones, as opposed to fixed signals, like crying and laughter, and vegetative vocalisations, drawing comparisons between humans and other mammals. Vegetative sounds, resulting from bodily functions associated with respiration, swallowing an digestion, may nevertheless have social significance in many species: for example, sneezing may indicate the presence of a potentially dangerous substance, and the species is thus able to interpret sounds or gestures that are not specialised for communication. Fixed signals, with origins in bodily responses unrelated to communication, may have been moulded to the purposes of communication through natural selection. Their form is quite stable: developmental changes in the form of human fixed signals are notable with, e.g., age, but do not prevent the recognition of a cry or a laugh at any age. Vegetative sounds are relatively identifiable across species, whereas fixed vocal signals are more species-specific. Protophones, in contrast, have no biologically specified values as signals, nor are they associated with specific emotional states. Protophone play needs no intention to communicate either. These sounds do not have to be produced, nor do they have to be produced within a narrow range of acoustic parameters. They have the potential to be moulded to situations, thereby showing a primary feature of Conventionality (discussed in Chapter 12), typical of language in its embryonic state. Often, the first associations between protophones and intention tend to be made up by the child, i.e., with no intervention from adult models. Protophones, in this way, "cut a path on the way to a lexicon" and emerge as the "specific precursors to speech" (p.193). They can be produced independently of any signalling value and have therefore the potential for association with new values.

    Chapter 11 discusses the interest in the origins of human language throughout the ages, to strike a position of compromise: the differences between human and nonhuman communication systems may provide insight about our origins, whether the differences lie in our mental or our vocal attire. Oller acknowledges his debt to17th and 18th century thought in laying the foundations for the systematic development of a general theory of properties attempted in this book. In the same sense that infant speech cannot be assessed through mature language models, it is "in the context of a species-independent theory of infraphonological properties [that] it is possible to make insightful comparisons among different species" (p. 209). >From these comparisons, the special features of human action and capability, that are present from the first months of life, appear as clearly unique, presaging the elaborate ability to communicate through speech.

    Chapter 12 specifies the dimensions along which communication systems may vary, in the form of 18 properties that highlight the many routes through which species differentiation may take place. The properties, simply listed in this review along with the briefest explanation for each, are: 1. Contextual Freedom, the intentional control over vocalisations. 2. Free Expressivity, the ability to express oneself through vocalisations of any sort. 3. Directivity, the display of vocalisations for the production of social effects. 4. Interactivity, social connection through vocal turn-taking. 5. Imitability, the adaptation to community-determined signals. 6. Designation, the ability to share reference to entities. 7. Conventionality, the assignment of values of any kind to signals. 8. Arbitrarity, where there is no discernible similarity of signal and meaning. 9. Semanticity, analytical reference to a class of entities. 10. Displaceability, reference to absent entities. 11. Propositionality, the use of multiword utterances. 12. Signal Analysis, the manipulation of acoustic parameters of speech. 13. Categorical Adaptation, the ability to decompose syllables into their feature components. 14. Syllabification, the use of well-formed syllables. 15. Recombinability, the combination of syllables into novel patterns. 16. Rhythmic Hierarchy, the organisation of syllables within breath groups. 17. Segmentation, the use of segmental recombination. 18. Hot-Cool Synthesis, the production of graded vs. discrete meanings. Each property is analysed in turn, and their availability in both human and other primates is gauged through an authoritative review of research on nonhuman (young) primates. The discussion also points to where parallels may obtain between ontogenetic and phylogenetic language development, on the basis of the implicational hierarchy naturally evident in these properties.

    Chapter 13 offers a speculative scenario of the phylogeny of language, one of many possibilities, as Oller points out, that may be consistent with the facts of vocal development as embodied in the properties hierarchy. The scenario is presented in 7 successive scenes corresponding to as many evolutional stages, in accordance with Oller's view that language may have evolved gradually. These scenes involve "features that appear consistent with other aspects of empirical paleontology" (p.337), and encompass developmental stages parallel to those found in human infants up to the 2- and 3-word stage. Through this scenario, Oller distances himself from the view that current speech ontogeny recapitulates phylogeny by virtue of genetic programming, underscoring instead the claim that "to the extent there is similarity of ontogeny and phylogeny in speech, it may be the result of the fact that both modern infants and ancient hominids have been subject to similar constraints of a natural, logical, infrastructural sort. There are inherently natural ways that a vocal communication system might develop."(p.317).

    Chapter 14 returns to the intrinsic difference between speech and fixed signals, to give a comparison of fixed signals across human and nonhuman system. Guided by infrastructural modelling, the comparison specifically purports to highlight substantial similarities among these. Universal properties appear to underlie animal communication capabilities in general.

    Finally, Chapter 15 summarises the book and recapitulates the main points. By leaving operational-level units of mature speech out of descriptions of infant vocalisations, "we found stages of development that had eluded prior generations of scholars" (p.356), which in turn opened the ground for a universal comparison of communicative systems . Furthermore, "the key to sensible application of developmental research in evolution is the use of infrastructural modeling [where] both ontogeny and phylogeny are presumed to be governed by a common set of properties and principles of potential infrastructure." (p.364).

    Critical Evaluation

    Oller's infraphonological model provides ground-breaking insight into language ontogeny and phylogeny, and stands out as intuitively satisfying. The goal of the model is best expressed in the author's own words: "If properly formulated, these properties may constitute a stable set of logical possibilities from which systems of communication choose, and may constitute a species-independent, universal system of limits on the ways that vocal communication can be developed." (p.210). It makes good sense to treat communication systems from a common underlying perspective, avoiding the easy trap of analysing one system through the communicative lenses of another. Oller perceptively directs his analysis to the very beginning of the potential differentiation of the human and nonhuman lines, far before the time frames adopted in other literature on the evolution of language, and takes therefore nothing for granted. In his own assessment, rudimentary as some properties may seem, compared to full-blown human language and to corresponding current accounts of it particularly in the area of syntactic theory, Oller's contention is that such properties represent "critical departures from the vocal capabilities of other primates" (p.319). The universality of their application is highlighted throughout the book in several references to diverse animal communication systems, including mammals, cetaceans and birds. Mutatis mutandis, the reader is left with few doubts about the effective power of this model to identify, for example, so-called 'intelligent' electronic communication devices. Oller's claims emerge as all the more convincing through the way in which he gradually presents his model, indicating its potential ambiguities and pointing out issues to which the present state of our knowledge fails to provide an answer. This not only results in a lucid picture of what a scientific proposal should look like, it entices the reader to look for answers to the issues left open. His claims are also based on an impressive amount of empirical research. This is true of the speculative scenario presented in chapter 13 too, whose solid grounding in paleontological findings makes for fascinating reading about what could well have been our infra-articulate past. In reviews of literature, Oller's stance is equally cautious, making plentiful use of footnotes, excursions and forward references within the book itself, that tone down any sweeping, reductionist generalisations that the reader might be tempted to indulge in.

    In view of the depth and breadth of the issues covered in this book, a few words of disappointment are due on Oller's treatment of intonation. Although intonation is mentioned several times throughout the book, the proposed model offers no linguistically pertinent place for intonation either in the protophone inventory or the infrastructural properties. Intonation appears as an incidental addition to the fundamental protophone system, mostly to make it "more powerful" (p.224) through the superimposition of illocutionary force or the expression of emotion. This is particularly clear, for example, in the discussion of the Hot-Cool Synthesis property in chapter 12 and passim, where the gradient, emotional, hot, side of the dichotomy is manifested by uses of pitch, whereas the discrete, informational, cool, side is coded in syllables. The remarks that this synthesis is a "magical" property of human language (p.304) and "a means of coding a fundamental distinction between meaning and other communicative values" (p.306) seems to vouch for the stance that no linguistic meaning is coded by uses of pitch. The picture that emerges is that intonation, being the domain of emotions, is in fact equivalent to one of Oller's fixed signals, with predictable cross-language and cross-species meanings, which is synonymous with lack of linguistic meaning. The statement that "Human infants begin to use arbitrary vocal signals by 12 months of age, with the first words of the emergent lexicon" (p. 275) reinforces the view that intonation carries no arbitrary meaning. Protophones and words are taken as the building blocks of emergent speech and therefore, of full-blown language. It is not clear how the rich intonational system of a language comes to be acquired later than, or independently from, the segmental units of the same language. It is even less clear, indeed, how these units can be articulated without intoning, although Oller does sporadically refer to the imitation of intonation as occurring earlier than the imitation of syllables (pp.31, 179) and to richly intoned babbling (p.184, 305). The problems raised by this view become clear, for example, in the discussion of a putative example (pp.277-278) of a child using the syllable [ba] in many ways, including pointing at a ball and saying "[ba] with rising intonation, waiting for the adult to confirm that indeed the object is called ball". Oller concludes that "pairing a single meaning and sound with multiple forces", intonation apparently being a "force", provides evidence that "the word [ba] has achieved semantic status", that is, [ba] refers "analytically to the class of objects, balls". My point is, the same child could as well have been using the same rising intonation with several other syllables of its repertoire, in order to fix the semantic status of the tone. The infrastructural model seems to me to allow for an account of intonational protophones too. As it stands, the treatment of intonation in this book is, at best, ambiguous. At worst, it may foster the ingrained and erroneous popular belief that intonation is extralinguistic and plays a marginal role in vocal communication. Pitch modulation can convey emotional states, but so can the use of specific lexical units, in all languages. Depriving a universal model of communication systems of its intonational component unduly impoverishes, in my view, our understanding of the emergence of the speech capacity.

    [About the reviewer: Madalena Cruz-Ferreira teaches phonetics, phonology, morphology and general linguistics at the National University of Singapore. Her research interests include prosody, bilingual child language acquisition and Portuguese linguistics. mcfpacific.net.sg ]





    =================== Madalena Cruz-Ferreira mcfpacific.net.sg ===================