phonological representations, phonological awareness, and print decoding ability in children with

266 Pages·2006·1.12 MB·English

PHONOLOGICAL REPRESENTATIONS,
PHONOLOGICAL AWARENESS,
AND PRINT DECODING ABILITY
IN CHILDREN WITH
MODERATE TO SEVERE SPEECH
IMPAIRMENT

Dean Sutherland

A thesis submitted in fulfilment of the requirements for
the degree of Doctor of Philosophy

University of Canterbury
Te Whare Wānanga o Waitaha
Christchurch, New Zealand
June, 2006
The material presented in this thesis is the original work of the candidate except as
acknowledged in the text, and has not been previously submitted, either in part or in whole,
for a degree at this or any other University.
ii
Acknowledgments
The completion of this PhD study programme is a credit to the people who have
guided and supported my endeavours over the past 3 years. I am indebted to many people
who have made invaluable contributions to my learning and personal growth during this time.
My supervisor, Professor Gail Gillon, has provided excellent guidance throughout this study
programme. I admire her passion for helping young children overcome oral and written
language difficulties. I am extremely grateful for the first class coaching she has provided to
develop my research and writing skills. My first introduction to research was under the
guidance of Professor David Yoder. He has continued to cheer for me throughout the past 3
years. I have found his sense of humour a regular source of energy. Many colleagues,
students, and staff from the Department of Communication Disorders, and the wider
University of Canterbury community, have provided friendship, encouragement, and support.
For me, these relationships and interactions have highlighted the essence of communication. I
am particularly grateful to Dr Emily Lin for being so receptive and helpful with my statistical
enquiries.
A number of significant contributions to this study have been made by organisations
and people outside the University community. The Foundation for Research Science and
Technology has provided invaluable financial support through the Top Achiever Doctoral
Scholarship programme. Ministry of Education Speech-language therapists and preschool
teachers acted as referral agents to provide participants to join the study. I am extremely
grateful for the time and effort contributed by the children and families who took part in the
study. Karen Long, Brigid Moriarty, Elizabeth Quinn, and Dana Sutherland provided essential
input to establish that my data were accurate and reliable. My mother, Lorrane, has provided
unwavering love and support for our family, in addition to extra child care responsibilities
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while I have been “on the road”. This success could not have been achieved without the
ongoing love and sustenance provided by my best friend and wife, Dana. My children, Jesse,
Oliver, and Alexis, often wondered where Daddy went each morning, yet greeted me with
energising hugs every evening. This achievement is as much for them as it is for me.
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Abstract
The development of reading competency is one of the most significant pedagogical
achievements during the first few years of schooling. Although most children learn to read
successfully when exposed to reading instruction, up to 18% of children experience
significant reading difficulty (Shaywitz, 1998). As a group, young children with speech
impairment are at risk of reading impairment, with approximately 50% of these children
demonstrating poor acquisition of early reading skills (Nathan, Stackhouse, Goulandris, &
Snowling, 2004; Larivee & Catts, 1999). A number of variables contribute to reading
outcomes for children with speech impairment including co-occurring language impairment,
the nature and severity of their speech impairment as well as social and cultural influences.
An area of research that has received increasing attention is understanding how access to the
underlying sound structure or phonological representations of spoken words stored in long-
term memory account for reading difficulties observed in children (Elbro, 1996; Fowler,
1991). Researchers have hypothesised that children with speech impairment may be at
increased risk of reading disability due to deficits at the level of phonological representations
(Bird, Bishop, & Freeman, 1995).
Phonological representation deficits can manifest in poor performance on tasks that
require children to think about the sound structure of words. Knowledge about the
phonological components of words is commonly referred to as phonological awareness.
Identifying and manipulating phonemes within words are examples of phonological
awareness skills. Some children with speech impairment perform poorly on phonological
awareness measures compared to children without speech difficulties (Bird et al., 1995;
Carroll & Snowling, 2004; Rvachew, Ohberg, Grawburg, & Heyding, 2003). As performance
on phonological awareness tasks is a strong predictor of early reading ability (Hogan, Catts, &
Little, 2005), there is an important need to determine if children with speech impairment who
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demonstrate poor phonological awareness, have deficits at the level of phonological
representations. This thesis reports a series of studies that investigated the relationship
between phonological representations, phonological awareness, and word decoding ability in
children with moderate to severe speech impairment. A child with complex communication
needs (CCN) who used Augmentative and Alternative Communication (AAC) was also
examined to determine how the absence of effective articulation skills influences the
development of phonological representations.
The study employed a longitudinal design to compare the performance of nine
children (aged 3:09-5:03 at initial assessment) with moderate to severe speech impairment
and 17 children with typical speech development on novel assessment measures designed to
determine characteristics of children’s phonological representations. The tasks required
children to judge the accuracy of spoken multisyllable words and newly learned nonwords.
The relationships between performance on these tasks and measures of speech, phonological
awareness and early print decoding were also examined. Four assessment trials were
implemented at six-monthly intervals over an 18-month period. The first assessment trial was
administered approximately 6 to12 months before children commenced school. The fourth
trial was administered after children had completed 6 to 12 months of formal education. The
child with CCN completed three assessment trials over a period of 16 months.
Data analyses revealed that the children with speech impairment had significantly
greater difficulty (p<0.01) judging mispronounced multisyllable words compared to their
peers with typical speech development. As a group, children with speech impairment also
demonstrated inferior performance on the judgment of mispronounced forms of newly learned
nonwords (p<0.05). No group differences were observed on the judgment of correctly
pronounced real and nonword stimuli.
Significant group differences on speech production and phoneme segmentation tasks
were identified at each assessment trial. Moderate to high correlations (i.e., r = 0.40 to 0.70)
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were also observed between performance on the phonological representation tasks and
performance on phonological awareness and speech production measures at each trial across
the study. Although no significant group differences were observed on the nonword decoding
task, 4 of the 9 children with speech impairment could not decode any letters in nonwords
(compared to only 1 child without speech impairment) at the final assessment trial when
children were 6-years-old. Two children with speech impairment showed superior nonword
decoding ability at trial 3 and 4.
The within-group variability observed on the nonword decoding task highlighted the
heterogeneity of children with speech impairment. The performances of four children with
speech impairment with differing types of speech error patterns were analysed to investigate
the role of phonological representations in their speech and phonological awareness
development. The child with delayed speech development and excellent phonological
awareness at trial 1, demonstrated superior phonological awareness and word decoding skills
at age 6 years, although his performance on phonological representation tasks was
inconsistent across trials. In contrast, a child with delayed development and poor early
phonological awareness demonstrated weak performance on phonological representation,
phonological awareness, and decoding at each successive assessment trial. The child with a
high percentage of inconsistent speech error patterns generally demonstrated poor
performance on phonological representation, phonological awareness and decoding measures
at each of the 4 assessment trials. The child with consistent and unusual speech error patterns
showed increasingly stronger performance on the phonological representation tasks and
average performance on phonological awareness but limited word decoding ability at age 6.
The 11-year-old girl with CCN, whose speech attempts were limited and unintelligible,
demonstrated below average performance on phonological representation tasks, suggesting
that an absence of articulatory feedback may negatively influence the development of well-
specified phonological representations.
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This thesis provides evidence for the use of receptive tasks to identify differences in
the phonological representations of children with and without speech impairment. The
findings also provide support for the link between the representation of phonological
information in long-term memory and children’s speech production accuracy, phonological
awareness and print decoding ability. The variable performance of some children with speech
impairment and the child with cerebral palsy demonstrate the need to consider individual
characteristics to develop an understanding of how children store and access speech sound
information to assist their acquisition of early reading skills.
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Publications arising from this thesis
Sutherland, D., & Gillon, G. T. (2005). Assessment of phonological representations in
children with speech impairment. Language, Speech & Hearing Services in Schools, 36,
294-307.

Sutherland, D., & Gillon, G. T. (in press). The development of phonological representations
and phonological awareness in children with speech impairment. International Journal of
Language and Communication Disorders.
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Table of Contents
ACKNOWLEDGMENTS...............................................................................................................iii
PUBLICATIONS ARISING FROM THIS THESIS.............................................................................ix
TABLE OF CONTENTS.................................................................................................................x
LIST OF TABLES.......................................................................................................................xv
LIST OF FIGURES.....................................................................................................................xvi
LIST OF ACRONYMS AND ABBREVIATIONS...........................................................................xvii
CHAPTER 1. LITERATURE REVIEW...........................................................................................1
1.1 Introduction........................................................................................................................1
1.2 Phonological Representations...........................................................................................4
1.2.1 A definition of phonological representations....................................................................4
1.2.2 The nature of early phonological representations.............................................................5
1.3 Phonological Representations and Phonology Theory...................................................6
1.4 Phonological Representations in Models of Adult Spoken Word Recognition............7
1.4.1 Cohort model.....................................................................................................................8
1.4.2 Trace model.......................................................................................................................9
1.4.3 Shortlist model................................................................................................................10
1.4.4 Neighbourhood Activation model...................................................................................10
1.4.5 PARSYN model..............................................................................................................12
1.4.6 Section summary.............................................................................................................12
1.5 Phonological Representations in Developmental Models of Spoken Word
Recognition.............................................................................................................................13
1.5.1 Syllable Acquisition, Representation, and Access Hypothesis (SARAH)......................14
1.5.2 Developmental model of Adult Phonological Organisation (DAPHO)..........................15
1.5.3 Word Recognition and Phonetic Structure Acquisition (WRAPSA)..............................16
1.5.4 Section summary.............................................................................................................17
1.6 Phonological Representations and Early Speech Perception and Production...........18
1.6.1 Speech perception...........................................................................................................18
1.6.2 Speech production...........................................................................................................22
1.6.3 Studies of both speech perception and production..........................................................24
1.6.4 Section summary.............................................................................................................26
1.7 Phonological Representations and Speech Impairment...............................................27
1.7.1 Speech impairment and reading development................................................................30
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