facilitating word-learning abilities in children with specific language

252 Pages·2009·1.08 MB·English

FACILITATING WORD-LEARNING
ABILITIES IN CHILDREN WITH
SPECIFIC LANGUAGE IMPAIRMENT

Naomi Katharina Zens
MSLT

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

University of Canterbury
Te Whare Wānaga o Waitaha
Christchurch, New Zealand
May, 2009
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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.

Naomi Katharina Zens
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ACKNOWLEDGEMENTS

I would like to thank Professor Gail Gillon for her invaluable advice and
expertise throughout the preparation of this thesis. She has been an outstanding
mentor and provided me with excellent guidance throughout this study. Her
commitment to research has been a constant source of encouragement and inspiration
to me. I would also like to thank my co-supervisor Dr. Catherine Moran for her
support, encouragement, and enthusiasm throughout the last three years.
I would like to acknowledge the children and their families who participated in
this study. Working with the children and seeing their progress throughout this study
highlighted for me the importance of linking research to the clinical field. Thanks are
expressed to the teachers and principals for always being very welcoming and
supporting and for making the data collection possible.
I am very grateful for the assistance I received from Dr. Anne van Bysterveldt,
Kate Clark-Spohn, Karyn Carson, Sarah Berger, Cassandra Guignon, and Dr. Jason
Wong for their reliability work and editing. In particular, I would like to thank Pat
Coope, consulting statistician, for her invaluable advice on statistical analysis. Thanks
are also expressed to my colleagues at the Department for Communication Disorders
and in the PhD research Community at the College of Education.
I would like to acknowledge the financial support from the Department of
Communication Disorders, the College of Science, and the Royal Society of New
Zealand Canterbury Branch.
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The completion of this PhD programme would not have been possible without
the enduring love and support from my partner Nicolas, my family, and my friends.
Their constant encouragement and interest in my work has been a great source of
motivation throughout my studies.

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ABSTRACT

Children with Specific Language Impairment (SLI) often present with
difficulties in learning new words compared to age-matched children with typical
language development. These difficulties may affect the acquisition, storage, or
retrieval of new words. Word-learning deficits impact on children’s vocabulary
development and impede their language and literacy development. Findings from a
wide range of studies investigating word-learning in children with SLI demonstrated
that semantic and phonological knowledge are crucial to the word-learning process.
However, intervention studies designed to improve the word-learning abilities in
children with SLI are sparse. The experiments described in this thesis addressed this
need to understand the effects of interventions on word-learning abilities. Further, the
thesis describes the first investigation of word-learning abilities of New Zealand
school-aged children with SLI. Specifically, the following three broad questions are
asked:

1. What are the word-learning skills of New Zealand school-aged children with
SLI compared to children with typical language development and which
underlying language skills influence word-learning?
2. What are the immediate and longer term effects of phonological awareness
and semantic intervention on word-learning and language skills in children
with SLI?
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3. What are the error patterns of children with SLI compared to children with
typical language development when learning to produce new words and do
these patterns change following phonological awareness and semantic
intervention?

The first experiment compared the word-learning abilities of 19 school-aged
children with SLI (aged 6;2 to 8;3) to age-matched children with typical language
development and revealed that children with SLI presented with significant
difficulties to produce and to comprehend new words. After repeated exposure,
children with SLI caught up to the performances of children with typical language
development in learning to comprehend new words, but not on production of new
words. Correlation analyses demonstrated that there were no correlations between the
word-learning skills and other language measures for children with SLI, whereas the
word-learning abilities of children with typical language development were correlated
to their phonological awareness, semantic, and general language skills.
In the second experiment, it was investigated whether there were also
qualitative differences during word-learning between children with and without SLI
additionally to the quantitative differences as revealed in the first experiment.
Children’s erroneous responses during the word-learning tasks were categorised into
phonological, semantic, substitution or random errors. A comparison of the children’s
error patterns revealed that children with SLI presented with a different error pattern
and made significantly more random errors than children with typical language
development. However, after repeated exposure, children with SLI demonstrated a
similar error pattern as children without SLI. Furthermore, it was examined whether a
specific combination of phonological and semantic cues facilitated children’s learning
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of new words or whether there were word-specific features that facilitated children’s
word-learning. No facilitative word-specific features could be identified. Analysis
revealed that there were no significant effects of cueing on learning new words, but
specific patterns could be derived for children with SLI. Children with SLI learned to
comprehend more words that were presented with two semantic cues or one
phonological and one semantic cue and learned to produce more words that were
presented with two phonological cues.
In the third experiment, the effectiveness of a combined phonological
awareness and semantic intervention to advance children’s word-learning abilities was
examined. Nineteen children with SLI (same participants as in experiment 1)
participated in this intervention study that implemented an alternating treatment group
design with random assignment of the participants. Children in group A received
phonological awareness intervention followed by semantic intervention, whereas
children in group B received the same interventions in the reverse order. Children’s
word-learning abilities were assessed at pre-test, prior to the intervention, at mid-test
after intervention phase 1, and at post-test, immediately following the completion of
the second intervention phase. Each intervention itself was effective in significantly
improving children’s fast mapping skills, however, gains in children’s word-learning
abilities were only found for children in group A for production of new words.
Extending the findings of the intervention effectiveness of phonological
awareness and semantic intervention on word-learning as reported in experiment 3, it
was investigated in experiment 4, whether the implemented intervention additionally
influenced the error patterns of children with SLI. The erroneous responses of
children with SLI on all word-learning probes at pre-, mid-, and post-test were
categorised into the same error groups as described in the second experiment
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(semantic, phonological, substitution, and random errors). The error analyses revealed
that children’s error profiles changed during the course of intervention and treatment
specific effects on children’s erroneous responses were found. Post-intervention,
children who received phonological awareness followed by semantic intervention
displayed the same error patterns as children with typical language development,
whereas children who received the same interventions in the reverse order maintained
the same error pattern as displayed at pre-test.
The final experiment examined the longer-term effects of the combined
phonological awareness and semantic intervention reported in experiment 3 on the
language and literacy development of children with SLI. Eighteen of the 19 children
with SLI, who received the intervention reported in experiment 3, were available for
re-assessment 6 months after the completion of the intervention. The children (aged
7;1 to 9;2 years) were re-assessed on a range of standardised and experimental
measures. Data analysis revealed that 6 months post-intervention, all children were
able to maintain their gains in phonological awareness, semantic, and decoding skills
as displayed immediately after the intervention. Children’s general language and
reading skills significantly improved following the intervention; however, children
who received phonological awareness intervention followed by semantic intervention
displayed significantly better reading outcomes than the children who received the
same interventions in the reverse order.
This thesis revealed that a combination of phonological awareness and
semantic intervention can enhance the word-learning abilities of children with SLI.
The combined intervention approach was also effective in additionally improving
children’s general language skills and the reading of single non-words and real words,
as well as connected text. The immediate and longer-term intervention effects provide
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