Motor Speech Disorders

A Cross-Language Perspective

Nick Miller, Anja Lowit

• Publisher: Multilingual Matters
• Year: 2014
• Print ISBN: 9781783092321
• eBook ISBN: 9781783092345
• Topic: Medicine
• Subtopic: Adult Education

Motor speech disorders are a common accompaniment of a whole range of neurological conditions, from stroke, brain injury and Parkinson's disease through to many rarer conditions. This book aims to aid understanding of the nature of motor speech disorders from a cross-language perspective, in contrast to the largely English-centric nature of research and practice recommendations to date. The book looks not just at how these motor speech disorders are assessed and treated in other countries, but also examines how underlying speech impairments differ according to the language someone speaks. The book studies the underlying neurological, neurophysiological and neurophonetic characteristics of motor speech disorders in different language contexts, and discusses the implications these have for clinical rehabilitation. This significantly adds to debates around the theoretical understanding and clinical management of motor speech disorders.

1 Introduction

Nick Miller and Anja Lowit

What is This Book All About?

This book is about motor speech disorders (MSDs), about aspects of their assessment and treatment, about understanding the underlying neurophysiological and neuropsychological disruptions that bring about disorders of speech motor control. More precisely, the book is about what we can find out about these disorders from a particular perspective – cross-language studies.

MSDs are a cover term for problems with voice production/phonation and articulation due to neurological damage that impairs the planning and execution of movements required to produce speech (we offer an introduction to the field later for those not familiar with it). Disruption may affect one or more of the processes and actions underlying speech production, for example dysfunction in the ‘selection’ of the sounds required to say a word, problems in the planning of the movements needed to produce those sounds. Disruption may alter the transmission of nerve impulses between parts of the brain involved in executing the planned movements, cause difficulties with transmission of these impulses between the brain and other parts of the central nervous system and/or problems with relaying the impulses out via the peripheral nervous system to the muscles involved in articulation. The muscles active in speech output range from the diaphragm and thorax involved in the control of in- and expiration, via the larynx for phonation and the velum for regulating the degree of nasality, to the tongue, lips and mandible. These disruptions may affect any or all of breathing, phonation, resonance and articulation and in turn the ability to produce a voice loud and clear enough to be heard, articulation precise enough to deliver intelligible speech and variations in stress and intonation patterns necessary to convey suprasegmental aspects of meaning for the language a person speaks.

There are countless tomes and myriad articles written on MSDs, and so we already know a great deal about them. But, there is one big proviso to most of what we have to say – what we know about MSDs, how to recognise them, how people classify them, their differential diagnosis and many of the clinical practices around their assessment and treatment, rest predominantly on studies of speakers of English (and within those mainly American speakers) and structurally and phonologically closely related Indo-European languages. Such a narrow perspective in the field of communication always runs the risk of producing theories and practices that may not be universally applicable and may even be wrong when applied beyond the narrow confines of the linguistic and social contexts in which they were developed. This provides the rationale for this book.

Studies of MSDs do exist in other languages, most notably Chinese, German, French and Japanese (see chapters later in the book). A cross-language dimension, though, has been largely lacking, especially when it has come to the development of theories around speech motor control and its breakdown, though studies of deaf sign language users who have different neurological conditions do provide a marked exception here, as elucidated in a later chapter. This book aims to redress some of that imbalance. It contains two sections. The first part provides an introduction to MSDs and related areas in a cross-language context. The first three chapters set the scene, defining what we mean by cross-language studies, providing background information on MSDs for those who are not that familiar with this group of communication impairments, and discussing the fundamentals of assessing and treating MSD in a cross-language context. These chapters are followed by selected topics that demonstrate the progress made in the understanding of MSDs and related areas from cross-language studies and the kinds of issues that need to be considered in further investigations in this area. The second half of the book gathers overviews from a range of languages around the world. Each chapter contains a summary of the segmental and suprasegmental features of the language that set it apart from English, and discusses assessments and treatment programmes that have been developed for this medium. In addition, they offer a flavour of the status of knowledge on MSDs in those languages and begin to look at the nature of similarities and differences between languages or types of language that could form the basis of future cross-language investigations to advance our understanding of MSDs and speech motor control in general.

There is one more dimension implicit in this book. Another angle from which researchers have viewed communication to gain insights into brain–language relationships, clues to how language and sound processing reflect neurological processing, has been the study of speech and language breakdown, whether in developmental disorders or in acquired disorders of language and speech after stroke, head injury or in other neurological conditions. By examining what breaks down, and in what ways, in association with lesions in which sites, researchers have sought clues to the central variables in speech motor control and how normal, healthy processing takes place.

It is this dual speech pathology and cross-language line of enquiry that forms the backbone of this book. On the one hand, what clues are there to universals of speech and how might these address issues in our knowledge and conceptualisation of MSDs?; on the other hand, what implications do language-specific manifestations and variations in the universal tendencies have for the support and management of people with MSDs? In more specific example terms, on the one hand, what does apraxia of speech or ataxic dysarthria look like in different languages, but on the other hand, does an examination of apraxic breakdown in diverse languages uncover clues to or settle theoretical arguments as to the precise nature of apraxia of speech? The perspective to the fore in this book is a clinical one. However, through this there is a much broader currency in terms of how findings from these fields might inform the development of neuropsychological and neurolinguistic theory, what they have to tell us about brain–language relationships and how they contribute to our overall understanding of language and speech.

Part 1

Setting the Scene

2 Introduction: Cross-Language Perspectives on Motor Speech Disorders

Nick Miller, Anja Lowit and Anja Kuschmann

The Rationale for Cross-Language Studies

As the name implies, such studies entail comparing and contrasting the appearance, behaviour, form and functioning of a given variable across different languages. Cross-language perspectives have long formed an important avenue for the advancement of theoretical and applied studies in language and sound structure, in the laboratory, classroom and clinic. In the sphere of language (as opposed to speech and voice) this has involved, for instance, studying how different languages signal past tense, how they mark negation, how certain areas of the lexicon are organised (e.g. colour naming, kinship terms, prepositions). More recently, researchers have examined neural correlates of possible divergences (Liu et al., 2013). In relation to speech motor control, analyses have included the contrasting relationships between prosody and syntax; a comparison of vowel systems; specific variables such as voice onset time (Cho & Ladefoged, 1999), sensory-motor constraints on sound inventories (Lindblom, 2000; Lindblom et al., 1983), motor control (Chakraborty, 2012), attempts to capture rhythmic variation across languages (Loukina et al., 2011) and notions of language-specific articulatory settings (Gick et al., 2005; Laver, 1978; Mennen et al., 2010).

Through such scholarship, cross-language studies endeavour to derive theories of language functioning that are not tied to standard average European (SAE) or any other restricted language group, or they seek to test out theories and practices developed in one language to examine if they are equally applicable or require modification when applied to another language (Bozic et al., 2013). In the 1930s, the American linguist Benjamin Whorf introduced the label SAE to refer to modern Indo-European languages that share a number of phonological and grammatical similarities and which constituted the vast majority of the languages on which theories of language form, function and processing were based at that time. He argued that over-reliance on SAE in investigations of language universals had lulled researchers into the false sense that these commonalities divulged natural or even universal properties of language, when in fact they were peculiarities of the SAE group. Whorf’s studies of Hopi and other American indigenous languages amply illustrated the flaws in such argumentation. Admonitions regarding confounding surface forms with underlying properties persist to the present (Haspelmath, 2010, 2012).

Research along these lines has informed debates on the classification of language types and families, the development of linguistic theory, and has contributed to theories and practice in foreign language teaching and learning. One branch of the field has emphasised investigations into the differences between languages, into the different ways they function or are used. An arguably more potent line of enquiry in cross-language studies, however, has concerned the focus on commonalities across what on the surface might appear diverse and divergent systems, a focus not on the divides but on the shared. Among all the seemingly endless variety in sound, syntactic and semantic structures between languages, what clues are there to the fundamental, shared properties of the ways in which languages and sound systems are organised, operated and processed?

Studies have tackled issues around the general properties of syntax and morphology and the relationship between them, the semantic structure of utterances; closer to motor speech issues, scholarship has sought to establish the units of speech control that generalise across all languages, how do segmental and suprasegmental control relate, how are they integrated, what are the properties of syllables and concatenation of syllables, what light do comparisons throw on the debate around the phonology–phonetics division (or not). In this fashion the aim has been to construct theories concerning what aspects of language, and from the point of view of this book what aspects of speech motor control, reflect universal dimensions of how spoken languages work and insights into the brain systems that support them vs which aspects represent only language-specific adjustments to universal elements; what clues does this give to the unique properties of human language, and vitally, how do these underlying regularities reflect brain functioning, what insights do they deliver into neuropsychological, neurolinguistic and neurophysiological aspects of brain organisation and operation?

Cross-Language Studies in Speech and Language Pathology

Before proceeding to introduce the field of cross-language studies in motor speech disorders (MSDs), this section offers selective examples from studies in germane areas of speech language pathology where cross-languages have been more prevalent for some time, to give a flavour of the directions and power of cross-language studies and illustrate the potential of cross-language insights to generate advances in knowledge and practice.

The field of aphasia provides a prime example. The understanding of agrammatic aphasia was revolutionised through cross-language comparisons (Bates et al., 1991; Menn et al., 1995, 1996; Paradis, 2001). Within English, it had been conceptualised, as its label reflects, as a breakdown in syntax, with characteristic ‘telegrammatic’ output from the omission of function words and difficulty with word order. How, though, would such a conceptualisation, if it was to be universally applicable, be manifest in a language where there are few or no function words, where grammatical relationships are signalled (primarily) via noun and verb inflection? How would word order difficulties be manifest in a language with largely free word order?

Within the same debate much was made in research prior to cross-language studies of agrammatism of the differences between passive and active sentence production and comprehension, or between ‘do’ questions and ‘is’ questions (‘do dogs miau?’, ‘is it raining?’). If agrammatism represents a problem with syntax, then a more complex syntactic process (passives and ‘do’ questions in English were considered more complex than active voice and ‘is’ questions) should prove more problematic for speakers. Numerous studies purported to conclude this. What though of languages where the passive construction was actually less complex than or equally complex syntactically to the active structure or where different interrogative structures were formed in a variety of contrasting ways to English? Did the same divisions hold? In short, the answers were nowhere near as clear-cut as theories of agrammatic breakdown based on English would have led one to presume (Bates et al., 1999; Wulfeck et al., 1991).

The outcome of these cross-language studies in aphasia resulted in a radical reconceptualisation of what had been variously termed Broca’s or agrammatic or non-fluent aphasia. New theories (e.g. Bastiaanse et al., 2011; Bates et al., 1991; Friedmann & Shapiro, 2003; Macwhinney, 1987; Menn & Duffield, 2013) were developed that sought to capture and explain the common denominators across languages in the types of breakdown seen after brain damage, that attempted to delve below purely surface syntactic manifestations and theories based on these. This has led to far deeper insights into universal aspects of syntactic processing and output and our understanding of aphasia.

Closer to speech output, the field of dysfluency research has provided further examples of the benefits of a cross-language approach. Irrespective of which language someone stutters in, the types of dysfluency that arise appear to be universal – there are blocks, hesitations and prolongations in Russian just as in English or Hausa. However, what this surface similarity hides is that there is not equality across languages in the proportion of different stuttering moments (blocks to prolongations etc.), nor the loci of dysfluencies in terms of on what (kinds of) syllable or word or phrase they occur and where in the phrase they fall. Investigations into this variability have disclosed important aspects around the aetiology and manifestation of stu...

Table of contents

• Cover-Page
• Half-Title
• Series
• Title
• Copyright
• Contents
• 1 Introduction
• Part 1 Setting the Scene
• Part 2 Language Specific Profiles and Practices