An Emergence Approach to Speech Acquisition

Doing and Knowing

Barbara L. Davis, Lisa M. Bedore

• Publisher: Psychology Press
• Year: 2013
• ISBN:
  9781135067779
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

The central assertion in this volume is that the young child uses general skills, scaffolded by adults, to acquire the complex knowledge of sound patterns and the goal-directed behaviors for communicating ideas through language and producing speech. A child's acquisition of phonology is seen as a product of her physical and social interaction capacities supported by input from adult models about ambient language sound patterns. Acquisition of phonological knowledge and behavior is a product of this function-oriented complex system. No pre-existing mental knowledge base is necessary for acquiring phonology in this view. Importantly, the child's diverse abilities are used for many other functions as well as phonological acquisition.

Throughout, an evaluation is made of the research on patterns of typical development across languages in monolingual and bilingual children and children with speech impairments affecting various aspects of their developing complex system. Also considered is the status of available theoretical perspectives on phonological acquisition relative to an emergence proposal, and contributions that this perspective could make to more comprehensive modeling of the nature of phonological acquisition are proposed.

The volume will be of interest to cognitive psychologists, linguistics, and speech pathologists.

1

The Problem

Overview

The young child’s ability to integrate physical speech perception and production capacities for building a neural cognitive knowledge base about her ambient language phonology is a uniquely human achievement. Between birth and four or five years of age, children’s biologically based capacities, embodied in the production and perception systems, allow them to perceive, process, and produce a broadening array of ideas about their world. A growing phonological knowledge system grounded in neural structures and cognitive function provides the organizational means to interpret and express these increasingly complex messages. At the same time, the child’s social environment expands from intimate parent–child interactions to links with an increasing diversity of communication partners. Children implement this heterogeneous and dynamically changing behavioral-cognitive-social system, driven by the functional goal of sending and receiving their broadening array of ideas about the world.

Theoretical perspectives about the nature of phonological acquisition abound. We will discuss them throughout this narrative. However, in a context of multiple competing options for understanding acquisition of phonology, our central goal is to evaluate the strength of an emergence perspective for this central component of spoken language. A primary question arises immediately: What is emergence? To start this discussion, we are going to propose a short working definition.

Phonological knowledge and organized behavioral patterns for coding that knowledge arise out of interactions among diverse physical, cognitive, and social systems that are accessible within the young child’s world. The child’s physical capacities include her abilities for processing perceptual input, neural-cognitive storage and retrieval capacities, and increasing ability to produce intelligible speech output. These physical or embodied capacities are used by the child to connect with the outside world through social capacities for sustaining interactions. Other people provide relevant social input for what and how to deploy components of the phonological system in communicating.

In an emergence view, all of these components are necessary to account for complex phonological capacities in young children that support growth toward intelligible speech patterns and comprehensive ambient language knowledge. Crucially, none of the components of this complex system is uniquely causal of the eventual product in an emergence view. While all may be necessary, none is sufficient to facilitate acquisition of the phonological component of language. We assert that available theoretical perspectives devoted to understanding acquisition of phonology are insufficient to model the overall process. An integrative view based on tenets of emergence can enable understanding the process of phonological acquisition comprehensively.

Interaction is a critical term that we employ throughout our narrative as a basic principle underlying our concept of emergence. Interaction refers to the kind of observable properties that occur based on the combined or reciprocal action of two or more physical systems. For example, perceptual and neural systems or individual children and caregiver social dyads may interrelate with one another. These physical systems and individuals within social relationships have an ongoing and reciprocal effect on one another.

The idea of a two-way effect is also essential to this concept of interaction. A one-way causal effect might be indicated if the perceptual system driving the neural encoding of knowledge had no interactions with the child’s previous experience while she constructed an ambient language knowledge base. In social interactions, a one-way effect might be postulated if the child’s maturation (e.g. Fodor and Katz, 1964) was the only factor seen as responsible for triggering of ambient language phonological knowledge. Two-way effects encompass diverse systems and their reciprocal interactions with each other across acquisition.

Interaction relates to the moment-by-moment experiences in the young child’s life that evidence the working of the dynamic and complex system. A closely related term is interconnectivity. Interconnectivity implies that all the components of a complex system change and are changed by one another dynamically across acquisition. Interconnectivity is the result of the multiple interactions between the child and her environment that enable the emergence of phonological knowledge and behavioral patterns.

So what are the components that serve emergence? Several unique and interconnected strands compose our view of the acquisition of phonological knowledge. The first is the child’s internal production, perception, and neural-cognitive capacities. These are the abilities that the child brings to the task of phonological acquisition. They can be seen as embodied in the sense that they are founded in the child’s own bodily “equipment” for accomplishing this task. It is important to emphasize that “internal” refers to bodily abilities that grow and change with interactions of the child and the environment as well as with maturation. In an emergence view, they are not merely innate static properties that reveal phonological a priori phonological knowledge as the child matures. These capacities are critical and active components of the complex system.

Child internal capacities by themselves do not explain acquisition of phonology. A second factor is found in the child and adult’s reliable capacities for social interaction. Capacities to initiate and sustain social interactions reflect a complementary and necessary set of factors for the child’s internal physical capacities of perception, processing, and producing vocal output. These socially mediated links between the child’s core physical capacities and available input from her environment drive incremental refinements in neural structure and function (Mareshal et al., 2007) necessary to encode cognitively based phonological knowledge.

The social and cultural input from the environment illustrates a third dimension. The surrounding social environment refers to communication partners who employ the child’s ambient language phonological code in culturally appropriate ways to produce relevant and salient messages for her. This external scaffolding also creates functional pressure on the young child for intelligible communication. Input regarding precision of the sound qualities the child needs to produce for intelligible communication is readily available in daily social interactions with familiar communication partners (Lee et al., 2008). This rich matrix of environmental input sustains the young child’s need to function for survival (Locke et al., 1995). It also provides critical information to the child about learning to use the phonological component of language to code linguistically based communicative functions (e.g. to request or to refuse).

Critically, in an emergence perspective, these three components are not specific to language acquisition, or even to humans. In this regard, we will make the argument throughout that they are domain general rather than language dedicated. In addition, a single factor among these interconnected components of the system cannot be causal. Rather, the child’s process of successful acquisition depends on the integrated whole interacting dynamically, and is reflected in emergence of behavioral expressions and growth in underlying knowledge (Thelen and Smith, 1994).

Increasingly complex behavioral output makes manifest the increasing efficiency of interconnections among these diverse strands across the acquisition process. Growth in diversity of goal-directed movements observable through the child’s production of more types of sounds and sequences emerges in concert with the child’s abilities to refine and replicate frequently available words perceived in ambient language input from communication partners. At the same time, an increase in the child’s cognitive knowledge about the world, enabled via these social interactions, feeds into neural-cognitive storage of an expanding phonological knowledge base.

Why Consider Emergence?

What might be our motivation for exploring an emergence conceptualization for the phonological component of language? One primary incentive springs from an intuition that phonological acquisition presents a fruitful area for thinking about complexity. Language is one of the most complex and unique capacities that humans possess. Mastery of the phonological knowledge component of language allows the speaker to coordinate the production of an ordered set of complex peripheral production system movements and perceptual capacities with a knowledge base of relevant sound patterns to respond to input or initiate linguistic output. Rather than describing phonological patterns using the frequency of language forms themselves as an explanation for proposed universal aspects of knowledge, emergence perspectives offer the option of considering diverse sources of evidence for the complex patterns observable in children and in adult speakers and listeners. In particular, the peripheral speech production and perception mechanisms are foundational to building an eventual long-term neural-cognitive phonological knowledge store.

As a second motivation, we also want to consider emergence as a perspective on acquisition to understand individual variation in children’s pathways to achieving phonological knowledge and a behavioral repertoire (DePaolis et al., 2008; Vihman, in press). This issue is relevant at the level of the individual child in considering the relationship between central tendencies for acquisition of sound patterns in languages and the potential range of unique child differences. Central tendencies reinforce a notion of universal patterns as an approach to understanding the emergence of phonological form. In an emergence perspective, the actions of the body, in particular the perception and production system, are common properties of children’s biological makeup across all language communities. This common basis for observable vocal patterns implies that early periods of development may likely be similar across languages (Kern and Davis, in review, 2012).

Some classical phonological approaches have emphasized universal aspects of underlying grammar (UG) in the process of acquisition. There the status of proposed UG knowledge rather than the observable behavioral repertoire based on common biological capacities is central to understanding the nature of acquisition. In contrast, cognitively oriented approaches emphasize individual differences in the path to acquiring phonological capacities (Vihman and Croft, 2007; Ferguson and Farwell, 1975). There, the emphasis is on the proposal that each child learner individualizes the status of underlying phonological knowledge in formative periods based on use. Emergence approaches can potentially encompass both central tendencies and individual variations into the complex system underlying acquisition. Neutralizing this dichotomy may potentially produce a more comprehensive picture of acquisition. Emergence perspectives can potentially accommodate this neutralization.

An additional motivation for our interest in relationships between individual variations and central tendencies in phonological acquisition comes from our clinical background in speech language pathology. Speech language pathologists deal with a range of speech production and/or phonological disorders. The origins of these disorders can be found in perceptual (e.g. hearing impairment), motor (e.g. cerebral palsy), structural (e.g. cleft palate), neural-cognitive (e.g. traumatic brain injuries, genetic syndromes, mental retardation), and social (e.g. autism) dimensions of development. As well, many developmental speech disorders are functional, or of unknown origin, potentially based on either immaturity of speech production and/or perception mechanisms, or in differences in a child’s phonological knowledge base for the ambient language sound system.

Conceptualizing individual variability and central tendencies for clinical assessment and treatment is consistent with an emergent complexity perspective. Emergence offers a path to describing and understanding variations in starting points based on differences in perception, production, cognition, or social components of the child’s capacities for developing intelligible speech. Outcomes of intervention logically related to differences in these capacities can characterize individual child profiles of developmental disorder or difference. Accounting for known variations in starting points for acquisition based on perceptual, production, cognitive, and social differences are the “meat and potatoes” of clinical assessment and intervention planning for children with developmental differences.

As an example, an emergence perspective can offer a way of explaining how interventions at a variety of time points in development can produce similar treatment outcomes. Sharma and colleagues’ (e.g. Sharma et al., 2007, 2009) exploration of the neural consequences of hearing loss provides an exemplar emphasizing the impact of perceptual differences from an emergence perspective. Issues surrounding repair for prenatally determined clefts of the palate provide another opportunity to consider the importance of differences in the structure of the production system on phonological acquisition. Both of these examples of internal differences in biological subsystems illustrate a view of multiple system components responsible for emergence of phonology. We will return to this issue in some detail in Chapter 4.

What Emerges?

Critical to evaluating an emergence perspective is a definition of the complex system that we propose. In the case of phonological acquisition, contemporary theories have centered on both structural properties of language (i.e. consonant and vowel phonemes and their rules for combination) and the process by which language structures are decoded and encoded (i.e. memory, storage, and retrieval processes for phonological structures). Fully developed phonological skills permit adult speakers and listeners to generate and understand a potentially infinite array of linguistic messages. That is the long-term outcome of acquisition for young humans. Accordingly, we will review contemporary definitions of language to generate a necessary set of background information for considering emergence proposals on acquisition.

STRUCTURAL DESCRIPTIONS

A general characterization of language is “the words, their pronunciation, and the methods of combination used and understood by a community” (Colman, 2001). This definition is particularly apt for our endeavor, because it emphasizes the role of pronunciation of words, which includes both phonetic implementation and phonological knowledge within a shared ambient language community.

Within the broader realm of language, phonology is the store of knowledge that a speaker/listener has about phonemes and the rules for combining them in linguistic communication. Phonemes are sound types used to contrast meaning in a language (e.g. pig and big). These contrastive entities and their combinations differ across the 7,000 or so languages that are spoken today. To make these contrastive sounds and patterns, speakers exploit biologically available sound-making capacities differently. For example, Arabic contains guttural phonemes and Xhosa speakers utilize clicks for making meaning distinctions. Both sound types are produced using contact very far back in the throat. Neither of these sound types is used to contrast meanings in English or Russian.

A phonological knowledge system provides the tools to generate unlimited mutually understandable and unique utterances (Hockett, 1960) in adult speakers. This phenomenon is termed “duality of patterning.” That is, modern languages have both a meaningless level of structure composed of a finite list of sounds that combine in constrained ways to form words, and a meaningful level of structure in which those words combine to form sentences. Duality describes a fundamental property of languages whereby mature speakers can produce and understand a limitless array of meaningful words and utterances with a finite number of meaningless sound building blocks.

The phonetic and phonological systems interact with other levels of linguistic knowledge and production. Words code semantic conceptualizations for speakers. Words consist of sound sequences that a speaker must recognize in order to activate the corresponding meaning. Young children are more likely to remember and reproduce words with sounds and sound sequences that are within their productive repertoire (e.g. Storkel, 2006). Phonological working memory, or the ability to remember sound sequences, is associated with vocabulary learning throughout childhood and is a predictor of second language acquisition (Gathercole and Baddeley, 1993; Reuterskiold-Wagner et al., 2005; Santos and Bueno, 2003; Service, 1992).

Morphological knowledge is an additional aspect of linguistic form that is an aspect of mature language interacting with phonological knowledge for understanding and producing messages. Morphemes are t...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Table of Contents
• Chapter 1. The Problem
• Chapter 2. The Enabling Mechanisms
• Chapter 3. The Model
• Chapter 4. Vocalization and Pattern Detection Through Moving and Sensing
• Chapter 5. Refining Patterns of Complexity
• Chapter 6. Contemporary Theories and Paradigms
• Chapter 7. The Present State and a Future For Emergence
• References
• Index