Manual of Clinical Phonetics

Martin Ball, Martin J. Ball

• Publisher: Routledge
• Year: 2021
• ISBN:
  9781000334661
• Edition: 1
• Topic: Psicología
• Subtopic: Neuropsicología

This comprehensive collection equips readers with a state-of-the-art description of clinical phonetics and a practical guide on how to employ phonetic techniques in disordered speech analysis.

Divided into four sections, the manual covers the foundations of phonetics, sociophonetic variation and its clinical application, clinical phonetic transcription, and instrumental approaches to the description of disordered speech. The book offers in-depth analysis of the instrumentation used in articulatory, auditory, perceptual, and acoustic phonetics and provides clear instruction on how to use the equipment for each technique as well as a critical discussion of how these techniques have been used in studies of speech disorders.

With fascinating topics such as multilingual sources of phonetic variation, principles of phonetic transcription, speech recognition and synthesis, and statistical analysis of phonetic data, this is the essential companion for students and professionals of phonetics, phonology, language acquisition, clinical linguistics, and communication sciences and disorders.

PART I

Foundations of clinical phonetics

Introduction

A complete guide to clinical phonetics, which is the intention of this collection, needs to be able to provide an introduction to the basics of the field as well as to advanced theories and methods. This part of the Manual of Clinical Phonetics fulfils this role. Even for those who have received some training in phonetics or in communication disorders, there may well be some lacunae in their knowledge of these fields. For example, introductions to phonetics often concentrate on the segmental speech production area saying little about prosodic features or the transmission of speech, whereas speech science texts may be biased toward acoustics at the expense of speech production or speech reception. Even texts on auditory aspects of phonetics, or on audiology, may concentrate more on the mechanics of hearing and have little detail on how speech perception works. Finally, we need to bear in mind that this is a manual of clinical phonetics and thus that not all readers will be familiar with the range of communication disorders that can affect speech, even if they are well read in the study of typical speech. Part 1 of the Manual, therefore, provides a thorough foundation in both phonetics and speech disorders, allowing the reader to follow the content of later chapters which look in detail at specific aspects of phonetics and how these can be used to aid in the description and analysis of disordered speech.

This part of the book contains six chapters. The first of these, by Joan Rahilly and Orla Lowry, is a comprehensive account of articulatory phonetics. Clearly, in order to understand how the articulation of speech sounds can go wrong, one needs to understand how they are made. In this chapter, therefore, the production of vowels and of consonants is described. The chapter is not restricted to the sounds of any one language, however, and details of the whole range of sounds found in natural language are covered.

The second chapter, by Ioannis Papakyritsis, deals with acoustic phonetics. It introduces the main concepts in the study of acoustics and illustrates them by looking at both segmental and prosodic aspects of speech, covering both typical and disordered speakers. Elena Babatsouli describes the third main arm of phonetics—auditory phonetics—in the third chapter. This includes details of how hearing works, how it can be measured, and some of the ways in which it can go wrong.

The first three chapters, therefore, provide a grounding in what is traditionally thought of as the three arms of phonetics—articulatory, acoustic and auditory. However, there are two other areas which are important in phonetics and which are sometimes neglected: speech perception, and prosodic aspects of speech. In Chapter 4 Esther Janse and Toni Rietveld provide an introduction to the study of perceptual phonetics, including the important area of co-articulation, a topic sometimes neglected in clinical phonetic analyses. Orla Lowry, in Chapter 5, covers a range of suprasegmental features. These include those with potential for direct semantic impact (such as stress, tone, and intonation), and those with a more paralinguistic function (such as tempo, loudness, and voice quality), as both these types of suprasegmentals may be disturbed in various categories of disordered speech.

As noted above, this foundational part of the book is not restricted to the underpinnings of phonetics. To understand the contributions in the other three parts of this Manual, readers need to have a grounding in speech disorders as well as phonetics. The final chapter of this Part, by Martin Ball, provides just such a grounding. The chapter illustrates the wide range of communication disorders that impact speech, from child speech disorders, through acquired neurogenic disorders, to fluency disorders among several others. As each of these may impact speech production in different ways, the clinical phonetician needs knowledge of speech disorders as well as of phonetics.

1

ARTICULATORY PHONETICS FOR THE SPEECH CLINICIAN

Joan Rahilly and Orla Lowry

Introduction: What is articulatory phonetics?

It is no accident that the chapter on articulatory phonetics is the first one in the Foundations part of this book. Articulatory phonetics is indeed the foundational analytic, descriptive and therapeutic framework within which all speech clinicians must work to arrive at a clear picture of patients’ abilities in speech production. Without a firm grounding in and understanding of articulatory phonetics, the task of speech analysis is impossible. The term articulation captures how the organs of speech function independently and collaboratively, in order to create speech sounds. Our articulatory descriptions of speech therefore allow us to identify aspects of sounds from the point at which the speaker begins to produce the sound, to the final product that is released; the latter being the material which listeners then use to decode meaning. This final product, then, is a composite of underlying and contributory factors, and when it does not conform to typical speech norms, it is usually possible to highlight which organs of speech are responsible and how specifically their behavior has affected the speech output. In general terms, we can state that speech provides listeners with a number of clues: some of these indicate regional and social background but, for our primary purpose of clinical assessment, they can provide important insights into patients’ physical, physiological and even cognitive functioning. In the course of this chapter, we will introduce the key aspects of articulatory phonetics, beginning with a brief account of how and where speech sounds are initiated in the vocal apparatus, and moving on to a more detailed exploration of the standard framework for describing articulatory parameters.

A typical articulatory phonetic description requires us to identify what various organs of speech are doing during any given sound or stretch of sounds. Some of this activity is visible: we can usually see, for instance, when the upper and lower lips make contact with one another when we produce words beginning with b and m for instance, and when the upper teeth touch the lower lip in f or v (for the moment, we are using some orthographic letters which closely resemble phonetic symbols, and we will introduce a number of symbols as the chapter progresses, leading to a detailed account of transcription systems in Part 3). We may even see some tongue protrusion through the teeth when a speaker produces a th sound. Of course, many other speech sounds are produced inside the oral cavity (i.e. the mouth), and therefore cannot be seen or, at least, not easily seen. For t, sh or g, we cannot see the precise location of the sounds, but speakers can feel their tongue touch certain parts of their oral cavity in various ways. Furthermore, there are other sounds or aspects of sounds which cannot reliably be seen or felt and which need to be identified using the instrumental methods described in Part 4 of this book. Fortunately, the field of modern phonetics has developed convenient methods for describing the activity of speech sounds in considerable detail, drawing on the sort of visible, tactile and experimental knowledge we have outlined.

Overview of the stages of speech production

The first principle of articulatory phonetics is to recognize that there are four main stages in the production of any speech sound: initiation, phonation, articulation and, finally, the coordination which is required to make the relevant organs of speech work appropriately together. In practice, phonetic analysis tends to focus on the first three of these whilst acknowledging the importance of the coordination activities for creating fluent speech. To some extent, the terms initiation, phonation and articulation may seem self-explanatory (initiation for example, signals the beginning of the sound), but each has a specific, technical remit in articulatory phonetics. It is worth noting in passing that the term articulation, although used specifically to refer to the third stage of speech sound production, also invokes the broader sense of articulation in the entire production process. Each stage occurs in specific regions of the vocal tract (vocal tract is the term used to refer to the entire speech apparatus, with the larynx as the central element which subdivides the apparatus into lower and upper regions): initiation occurs usually in the sublaryngeal portion, phonation in the laryngeal area, and articulation in the supralaryngeal region. In each region, the sounds are formed and distinguished from one another by the actions of particular articulators and the location of this articulatory action, all of which will be discussed later in this chapter. Figure 1.1 provides an overview of the vocal tract, showing the location of the larynx and the key areas above and below it.

Figure 1.1Overview of the vocal tract.

Source: Courtesy of S. Qiouyi Lu.

We now move on to explain how speech sounds are formed in the vocal tract, with reference to the stages we have introduced above, i.e. initiation, phonation and articulation. To help readers combine the following descriptions with spoken examples of the sounds in question, we recommend reading this chapter whilst cross-referring to the online IPA charts provided by York University (http://www.yorku.ca/earmstro/ipa/index.html). With regard to atypical speech, we should note that the frameworks introduced in this chapter still serve as the descriptive basis for those working with all clinical speech types, with two caveats. First, what is regarded as a usual means for producing any given sound may not apply in various disorders. In the case of initiation, for example, Ball and Müller (2007) show the prevalence of non-pulmonic-egressive systems in clinical data, even though such systems are relatively rare in non-clinical speech. Second, there are instances where clinical speech cannot be described solely according to standard IPA criteria and, for this reason, the Extensions to the IPA for the Disordered Speech (known as extIPA) are used to capture atypical articulations such as consistent interdental protrusion of the tongue. For a detailed account of developments in phonetic notation, we urge readers to consult Esling (2010), particularly for his own elaborations of consonantal elements of both the IPA and extIPA, (both alphabets are discussed in Chapters 12 and 13 of this book), all in pursuit of providing as comprehensive a resource as possible for transcribing articulation in all speech types.

Initiation

Any sound, whether speech or not, must obviously begin somewhere, even though speakers and listeners rarely focus on the beginning point of sounds. The core component of sound is a moving body of air which is acted upon in various ways by the channels through which it travels. In musical instruments, for example, bodies of air are pushed through cavities of differing sizes and shapes, with varying force applied to the air at a range of points within the cavity in question. When we produce speech sounds, we are usually aware of what comes out of our mouths, i.e. the end point, without thinking of what precedes it, but the complete trajectory of a sound from start to finish is crucial in articulatory phonetics and it is a key element of the diagnostic process in therapy. The initiation of speech sounds requires speakers to set in motion the body of air somewhere within the vocal tract, usually by pushing air upward and outward through the system, although movement of air inward is also possible. These bodies of air, in whichever direction they travel, are known as airstream mechanisms. There are three such airstream mechanisms in speech, defined according to the particular poin...