26.2999, Review: Neuroling; Phonetics; Psycholing: Miller, Lowit (2014)

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Subject: 26.2999, Review: Neuroling; Phonetics; Psycholing: Miller, Lowit (2014)

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Date: Tue, 23 Jun 2015 13:45:23
From: Chris Plant [chris.plant.speech at gmail.com]
Subject: Motor Speech Disorders

 
Discuss this message:
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Book announced at http://linguistlist.org/issues/25/25-3203.html

EDITOR: Nick  Miller
EDITOR: Anja  Lowit
TITLE: Motor Speech Disorders
SUBTITLE: A Cross-Language Perspective
SERIES TITLE: Communication Disorders Across Languages
PUBLISHER: Multilingual Matters
YEAR: 2014

REVIEWER: Chris Plant, Griffith University

Review's Editor: Helen Aristar-Dry

SUMMARY

‘Motor Speech Disorders: A Cross-Language Perspective’ edited by Nick Miller
and Anja Lowit is a text that aims to draw attention to a much neglected area
of communication disorders. The text is divided into two parts with Part One
presenting chapters offering background information to motor speech disorders
(MSDs) and concepts applicable to cross-language comparison. Part two then
presents overviews of several languages, all of which aim to compare and
contrast the focal language with English, which is operationally used as the
‘model language’. 

Prior to Part One, Chapter 1, “Introduction”, by Nick Miller and Anja Lowit,
sets out to establish the premise and need for such a text. The chapter
highlights how much of the established research into assessment, description
and treatment of MSDs has been focused on English, particularly
American-English speakers and that this has led to theories of motor speech
production which may not be universally applicable. This leads Miller and
Lowit to state that this ‘narrow perspective’ poses problems when attempting
to apply theories regarding assessment and treatment of MSDs beyond the
linguistic, social, and cultural confines of English. Such a situation is
therefore argued to justify the need for the current volume, which jointly
integrates lines of enquiry from speech-language pathology and cross-language
comparisons.

Part One: Setting the scene

Part One of the text proceeds with seven chapters, each of which discusses
issues that are core to understanding MSDs within a cross-language framework.
Each of these chapters will be summarised in turn. 

Chapter 2, “Introduction: Cross-language perspectives on motor speech
disorders”. by Nick Miller, Anja Lowit and Anja Kuschmann, further lays the
foundations for the text as a whole. This chapter sets out the justification
for the current volume by claiming only partial truth for the assumption that
speech motor control is universal and therefore acquired impairments to speech
production, i.e. motor speech disorders, are similarly universal. It is argued
that speech production in any language is fundamentally reliant on
physiological processes responsible for respiration, phonation/voice,
resonance, articulation and prosody. However, different languages possess
different sound systems at both the segmental and suprasegmental levels, and
crucially, these differences result in different features leading to different
contrastive distinctions. Therefore, essentially the same impairment could
have very different consequences for speech production in different languages.
Several examples are given to illustrate this suggestion. For example, it is
suggested that languages with a large number of vowels will be more
susceptible to reduction in intelligibility as a consequence of impaired
tongue movement, because the positioning required to achieve vowel contrasts
will be more fine-grained compared to languages where there are fewer vowels.
The chapter proceeds to discuss the seminal research that led to the
development of the Mayo classification system of MSDs. While acknowledging the
importance of this work, it is also implied that the strict adherence to this
system, which was based on American-English listeners rating American-English
speakers with MSDs, has been and is continuing to be severely limiting when it
comes to broadening the understanding of the manifestation of MSDs in other
languages.

Chapter 3, “Motor speech disorders: What are they?”, by Anja Lowit, Nick
Miller and Anja Kuschmann, aims to provide a brief background to MSDs for the
reader unfamiliar with these forms of communication impairments. This chapter
essentially operationalises key terms and discusses each of the constituent
terms of the phrase ‘acquired motor speech disorder’. before defining and
describing ‘dysarthria’ and ‘apraxia of speech’. This is achieved with
reference to current theoretical debates, particularly regarding the basis of
apraxia of speech.

Chapter 4, “Motor speech disorders: Issues in assessment and management”, by
Anja Kuschmann, Nick Miller and Anja Lowit, provides an overview of issues
relating to both assessment and treatment of MSDs. Studies conducted on
English-speakers provide the foundation for the discussion with reference to
cross-language studies made where applicable. The focus of this chapter is the
Diagnostic Intelligibility Testing (DIT) which is a central theme of the
entire text. While classic texts in the area of MSDs do advocate the use of
intelligibility testing (e.g. Duffy, 2013), the current authors place far
greater emphasis on the value of DIT in informing description and diagnosis of
the MSD and also in informing treatment. It is discussed how traditional
intelligibility assessments often lead to an understanding of the degree of
severity in terms of a number, such as a percentage score of intelligibility.
Such scores in themselves however do little to aid understanding of how speech
is breaking down and therefore how treatment may aim to ameliorate these
difficulties. However, DIT is suggested to address these limitations of
traditional intelligibility assessments by systematically investigating the
speaker’s performance across various sound contrasts in terms of place and
manner of articulation and also voicing over a number of trials that allows
greater reliability in interpreting exactly which sounds and in which phonetic
contexts are particularly problematic. For example, it may be deduced that
intelligibility is reduced primarily in bilabial sounds in all word positions
and in all phonetic environments and such difficulties may be consistent with
observations of reduced lip function. Another key feature of effective DITs is
that they will be specifically designed to include items investigating
phonetic contrasts relevant within the target language. The authors suggest
that there is a general lack of valid and reliable DITs even when it comes to
English and then go on to provide principles to guide DIT construction for
English and indeed for any language. Suggestions for test construction relate
to the development of standardised and phonetically balanced reading passages
and also the selection of single words and sentences that are sensitive enough
to investigate the speaker’s ability to produce (and the listener’s ability to
perceive) “phonologically important contrasts for the language” (p47). 

Chapter 5, “Using English as a ‘Model Language’ to understand language
processing”, by Michael S. Vitevitch, Kit Ying Chan and Rutherford Goldstein,
suggests using English as the ‘Model Language’ when it comes to further
cross-language research into MSDs. Primarily this is based on the significant
amount of research that already exists for English. However, the chapter is
careful to emphasise that while extrapolation of findings in English-speakers
may be useful, caution needs to be taken as even minor differences between
languages can have very significant repercussions – a point which is
emphasised with the analogy that the human genome is 98% identical with that
of the chimpanzee. The chapter then reviews key phonological and
phonetic/phonotactic properties of English that may especially influence
speech production and which may therefore differ across other languages,
e.g.,. phonological segments and sequences, syllable frequency and structure,
word length, phonological similarity among words, and word frequency, drawing 
from all manner of psycholinguistic research conducted with healthy speakers
and making links to implications for MSDs throughout. The chapter concludes by
advocating for further research with healthy speakers from language
backgrounds other than English with particular attention to language-specific
aspects of phonology and phonetics and their influence on speech production
and recognition.

Chapter 6, “Cross-language studies in deaf signers”, by Martha E. Tyrone,
begins by presenting a description of the phonological aspects of sign
languages with emphasis on American Sign Language and British Sign Language.
The phonological variables identified in relation to signed languages include
movement, handshape, location, and orientation; and the chapter then goes on
to review the research evidence for how dysarthric and apraxic-type disorders
manifest to disrupt these dimensions in sign language users with various
presenting aetiologies (e.g. stroke, Parkinson’s disease, Progressive
Supranuclear Palsy). In general, the manifestations of dysarthria and apraxia
in sign language mirror the expectations based on aetiology and lesion
location; for instance, signers with cerebellar damage present with
uncoordinated sign movements just as speakers with cerebellar damage present
with uncoordinated speech movements. It is emphasised that just as with verbal
languages, there is a general lack of valid and reliable assessment materials
for investigating sign production deficits and also that a body of research
needs to develop around plausible treatments.

Chapter 7, “Apraxia of speech in bilingual speakers as a window into the study
of bilingual speech motor control”, by Marina Laganaro and Mary Overton Venet,
discusses the current challenges to assessment, diagnosis and management of
bilingual speakers with apraxia of speech. The chapter takes a
psycholinguistic perspective and discusses the suggestion of a mental
syllabary at the level of phonetic encoding that acts as a store of frequently
produced syllables. The key question addressed throughout the chapter is
essentially regarding whether syllabaries are language independent, i.e. that
there is one store for each language spoken, or whether a syllabary is shared
between languages spoken by the speaker. Through discussion of
psycholinguistic research and original data presented based on a pseudoword
repetition task with a Swedish-French bilingual speaker, findings are
presented whereby it is argued that the combined frequency of syllable
production across languages influences task performance. This leads to the
conclusion that syllabic motor plans are indeed shared across languages (where
they occur in both languages), as opposed to being language-specific.

Chapter 8, “Phonological and speech output in adult non-literate groups”, by
Dora Colaço, Ana Mineiro and Alexandre Castro-Caldas, presents a review of key
issues related to literacy and the development of phonological awareness (or
metaphonological skills). This is done on the premise that assessments that
are used to aid differential diagnosis of MSDs frequently involve aspects of
metaphonological processing. Initially, the distinction is made between
literacy and schooling to emphasise that these variables are often confused or
conflated and that they can indeed act independently (e.g. someone can attend
school yet be illiterate). The chapter then reviews research that addresses
the role of literacy in supporting metaphonological development. The research
reviewed focuses primarily on adult speakers and includes research involving
healthy speakers, speakers with aphasia, and bilingual speakers; it draws on
behavioural studies and also studies involving brain imaging in understanding
aspects of the neurobiology of bilingualism and metaphonological processing.
The chapter concludes by stating that while there has been a large amount of
research into metaphonological skills and influence on speech production,
there is still much to understand about how metaphonological processing may
differ across languages with different phonological systems.

Part Two: Language specific profiles and practices

Part Two of the text presents a further eleven chapters with ten chapters
discussing MSDs in particular language contexts and one concluding chapter. As
the majority of these chapters follow a similar pattern, individual summaries
of each chapter will not be necessary to gain a full appreciation of their
contribution towards the text as a whole. However, this should not under-state
the value of each of these chapters in providing the main substance of the
text.

The languages that are the focus of Chapters 9 through to 18 are: (9) Zulu and
Tswana, by Anita van der Merwe and Mie Le Roux; (10) Chinese (Cantonese and
Mandarin), by Tara L. Whitehill and Joan K-Y Ma; (11) Dutch, by Roel Jonkers,
Hayo Terband and Ben Maassen; (12) French, by Danielle Duez; (13) German, by
Bettina Brendel and Ingrid Aichert; (14) Hindi and Kannada, by R. Manjula and
Naresh Sharma; (15) Japanese, by Masaki Nishio; (16) Brazilian Portuguese, by
Karin Zazo Ortiz, Maysa Luchesi Cera and Simone dos Santos Barreto; (17)
Spanish, by Natalia Melle, María-Teresa Martin-Aragoneses and Carlos Gallego;
and (18) Swedish, by Ellika Schalling. 

The content of each of these chapters is consistent in presenting firstly a
description of the phonological system of the focal language(s) with
particular emphasis on identifying the aspects that are different from
English. The chapters then describe current availability of assessment and
treatment tools for use with speakers with MSDs. Then there is a review of
available research that has sought to provide descriptions of MSDs (both
dysarthria and apraxia of speech) in the focal language(s) prior to reviewing
research focusing on the treatment of MSDs in the language. The majority of
chapters then conclude by comparing and contrasting the findings of such
research with the respective findings in research on English speakers with
MSDs and/or presenting hypotheses about particular features of the focal
language(s) which may make MSDs in the language(s) different from those
observed in English speakers but which have yet to be empirically
investigated. 

The final chapter “Conclusion”, by volume editors Anja Lowit and Nick Miller,
in summarising the issues raised in the text seeks to address the questions
‘Where are we now?’ and ‘Where do we go next?’. In doing so, Lowit and Miller
reiterate the key approaches that the text has attempted to integrate in terms
of speech-language pathology and cross-language investigation and state that
all chapters presented have important contributions in this respect. The
chapter reflects on both the positives and the areas for further improvement
that the preceding chapters have highlighted. Some primary suggestions being
to simply expand the number of languages under active investigation in
relation to MSDs and also the need to increase cross-language comparisons in
speakers with MSDs. The chapter also naturally provides several possibilities
where the field has great potential for further research and development in
terms of description, underpinning theory, and clinical applications. 

EVALUATION

Overall, the text succeeds in providing a unique perspective on motor speech
disorders (MSDs) that does not conform to the now standard English-centric
view of MSDs as presented in a plethora of ‘classic’ texts. Often the approach
to linguistic and cultural diversity in these classic texts will simply be to
allude to the fact that the linguistic and cultural background of speakers
should be considered without actually detailing why and how this should be
done. While the topics and issues discussed in this text are obviously ripe
for further research, the issues discussed also have immediate relevance to
clinical practice. For a text that explores a generally under-researched area,
this is an uncommon achievement in presenting concrete suggestions for active
clinicians to improve their practices when it comes to working with speakers
with MSDs in languages other than English.

Similarly, it is easy to agree with the editors that the accumulated chapters
offer much to be disheartened with and much to be excited about with regards
to the current state of MSD practice across different languages. It is indeed
discouraging to be informed that there are no specific assessment tools for
some of the globe’s larger languages (e.g. Hindi). Similarly, the editors, in
their concluding chapter, allude to there being no resources available for
Arabic. Considering that there is no dedicated chapter focusing on Arabic, it
could be assumed that there is so little work related to MSDs and Arabic that
a chapter could not come to fruition. Equally, it is encouraging that this
text now provides a platform for these issues to be addressed, hopefully in
the near future. It is also encouraging to read that where research has been
conducted on treatment for MSDs, it appears that there is potential for
treatment approaches, originally developed with English-speakers in mind, to
have similarly beneficial effects for speakers from other language backgrounds

Part One of the text naturally presents the foundations and context for what
follows in Part Two - which is understandable. However, although the flow of
chapters in Part Two is easily appreciated, this is not always the case for
those in Part One. Some chapters, particularly Chapter 8 on the relationship
between phonological awareness and literacy, would benefit from being linked
more explicitly to the central themes of the text. While the broad relevance
to the issue of speech production is not in question, the link to MSDs was not
made explicit beyond stating that assessments used to differentiate between
MSDs sometime include tasks requiring metaphonological processing. Along
similar lines, one could argue that Chapter 6 on sign languages would have
been more effectively located within Part Two of the text, given that the
structure and content of the chapter is similar to those in Part Two and that
signed languages are legitimate languages just as English, French, and so on,
are.

Despite the above minor reservations, it is clear that the chapter authors
have been provided with a very specific remit by the text editors, and all
have succeeded in producing chapters that present clear and concise reviews of
the respective topics. With regard to chapters contained within Part Two, it
is clear that there is a great deal of difference between languages with
respect to how much research has taken place into MSDs. This is reflected in
the relative depth that chapter authors go into in differing sections. For
example, some chapters describe the sound system in great depth because of
significant differences with the sound system of English (e.g. Chapters on
Zulu and Tswana and French), whereas others present relatively brief reviews
(e.g. Chapters on Dutch and German). Some chapters are able to report detailed
descriptions of specific assessment tools that have been developed for the
focal language (e.g. chapters on Chinese, Dutch, Portuguese) whereas others
cannot do so because of the lack of such language-specific tools. Similarly
the sections reviewing treatment for MSDs vary in length and depth as a
consequence of the amount of research conducted in the focal language. This is
expected based on the premise of the text, but regardless each chapter feels
balanced and complete.

One of the key points that is consistently presented throughout the text both
explicitly and implicitly is the importance of Diagnostic Intelligibility
Testing (DIT) for the purpose of both describing the manifestation of the MSD
and also in identifying possible targets for treatment. Traditional ‘classic’
textbooks on motor speech disorders (e.g. Duffy, 2013) emphasise how
intelligibility assessment is one component of a broader protocol providing
information on a client’s ability to convey their message to a listener. The
current text emphasises the point that much intelligibility assessment that
occurs in research settings, and in particular in clinical settings, is not
diagnostic in that it does not inform which particular sound contrasts are
problematic, i.e. current practice tends to identify that intelligibility is
reduced but does not identify what leads to the reduction. Through the
explicit discussion of DIT in Chapter three and the descriptions of sound
systems of the focal languages in the chapters presented in Part two, the
reader is able to gain a fuller appreciation of the importance of the
diagnostic component of intelligibility testing. The descriptions of the sound
systems of the focal languages then provide a platform for the future
development of DITs in these languages which could reasonably be attempted by
anyone with a linguistic appreciation for the language in question and a
passion for MSDs.

While all chapter authors are well-respected researchers and authors who are
in good positions to comment on the current state of research into MSDs in the
focal languages, it is unclear as to the extent to which the reviews presented
are truly comprehensive and representative. Only one chapter explicitly offers
information about an information search protocol in terms of databases sourced
to inform the chapter content, although this still only accounts for a small
portion of the chapter (Chapter 16 on Brazilian Portuguese). Therefore readers
with an interest in MSDs in particular languages are still advised to conduct
their own further information searches for assessment and treatment tools and
associated research – which is naturally advised anyway but is especially
important considering that some chapters allude to ongoing and/or upcoming
developments.

A further point that would potentially improve the overall cohesiveness of
chapters in Part two is greater consistency in identifying whether the
assessment procedures and treatment methods discussed are solely the tools of
clinical research or whether they also represent procedures used by
clinicians. Some chapters, such as the chapter on Chinese, are quite explicit
in denoting that some tools have traditionally been the reserve of research
while clinicians have tended to use differing procedures. Other chapters offer
detailed descriptions of language-specific tools but do not specify the
prevalence of use of these tools in different domains. This is a significant
point considering that one of the suggestions for future developments in the
concluding chapter is for improved education away from ‘simple and misguided
direct translation’ of assessment and therapy materials into other languages. 

Overall, this text will surely become regarded as a seminal text in the area
of MSDs. Despite the clear emphasis on providing cross-language insights, the
researcher or clinician whose work is very much grounded in English-speakers
would stand to benefit hugely from reviewing the opening chapters to gain new
insight and direction into linguistic approaches to the description, diagnosis
and treatment of MSDs – a field which is still dominated by approaches centred
on identifying perceptually deviant features of a person’s speech (e.g.
breathiness, harshness, etc.). While this legacy from pioneering research by
Darley, Aronson and Brown (1975) is acknowledged and respected throughout many
of the text’s chapters, it is also abundantly clear, that the field needs to
move beyond the strict adherence to these approaches in order to progress –
hopefully the current text can facilitate this transition.

REFERENCES

Darley, Frederic., Aronson, Arnold., and Brown, Joe. 1975. Motor Speech
Disorders. Philadelphia, PA: Saunders.

Duffy, Joseph. 2013. Motor Speech Disorders: Substrates, Differential
Diagnosis, and Management (3rd edn). St Louis, MO: Mosby Elsevier.


ABOUT THE REVIEWER

Christopher Plant holds a Ph.D. in Speech and Language Sciences from Newcastle
University, UK (2012) and Masters Degrees in Psycholinguistics &
Neurolinguistics (University of Essex, UK) and Language Pathology (Newcastle
University, UK). His Ph.D. research focused on investigating the semantic
representations of nouns and verbs and their implications for conducting
speech and language intervention for people with aphasia. He is currently a
lecturer in speech pathology at Griffith University and also Central
Queensland University, Australia. He was previously a lecturer in speech
pathology at James Cook University, Australia. He can also be found on Twitter
@ChrisSPlant





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