Developmental dyslexia is widely believed to be caused either mainly or in part by an impairment of phonological representations. Although this hypothesis predicts that individuals with dyslexia should show deficits in tasks which require the use of implicit phonological knowledge, this has not yet been directly tested, as the evidence cited in support of this hypothesis usually comes from metalinguistic tasks which demand explicit awareness of phonological units. Additionally, since the ability to perform metalinguistic tasks which involve phonological segments can be enhanced by an individual’s competence in alphabetic literacy, the possibility remains that phonological skills may have been inadequately isolated from the influences of literacy acquisition in many cases. The study reported in this thesis investigated both the representations and the metalinguistic skills of a group of adults with a history of developmental dyslexia, examining areas of phonology which do and do not have orthographic counterparts. To isolate phonological skills from orthographic skills, the representations of conventional segmental contrasts (e.g. /k/ vs /g/) were compared with the representation of suprasegmental contrasts (as seen in minimal pairs such as ′toy factory and toy ′factory), which have no orthographic counterpart. Basic metalinguistic skills were tested by means of a phonological awareness task targeting both segmental and suprasegmental units, and phonological manipulation skills were tested using a Pig Latin task and a Spoonerism task, where participants were required to manipulate both segmental and suprasegmental units (e.g. extracting the segment /b/ from consonant clusters and the main stress from SWW or WSW stress patterns). The results showed that although the performance of the dyslexic group was weaker than that of the control group when tasks required the manipulation of either the segmental or suprasegmental components of words, no evidence was found for a deficit in the tasks which drew on implicit representations or basic metalinguistic skills. These findings suggest that the phonological deficit in dyslexia may be restricted to the ability to manipulate phonological units rather than in the representation of them per se.

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 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) 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. 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.

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 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) 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. 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.

The development of phonological representations remains a hot topic within both the developmental and neural network literature. Historically, theoretical accounts have fallen within one of two camps: the accessibility account which proposes that phonological representations are adult-like from infancy (Rozin & Gleitman, 1977; Liberman, Shankweiler & Liberman, 1989) and the emergent account which proposes that phonological representations become gradually restructured over development (Metsala & Walley, 1998; Ventura, Kolinsky, Fernandes, Querido & Morais, 2007; Ziegler & Goswami, 2005). Within this thesis we tested predictions made by the accessibility account and key variants of the emergent account using data from both behavioural (Chapters 2, 3 and 4) and neural network studies (Chapter 5). The novel measures used within Chapters 2 to 4 were devised to allow us to contrast implicit measures of phonological representation (PR) which probe the segmentedness of the representations themselves, with explicit PR measures which tap into children’s conscious awareness of phonological segments. Within Chapter 2 we present evidence that while explicit awareness of phonological structure is dependent on letter-sound knowledge, implicit sensitivity to the segments within words emerges independent of literacy. Within Chapter 3 a longitudinal study investigated the segmentedness of children’s phonological representations at the rime and phoneme level. These results demonstrate that implicit sensitivity to both rime and phoneme segments is driven by vocabulary growth and is not dependent on letter-sound knowledge. The results within Chapter 3 also suggest that, while awareness of rime segments emerges naturally through oral language experience, explicit awareness of individual phonemes is related to letter-sound knowledge. In Chapter 4 we explored the idea of global versus phonemic representation using a mispronunciation reconstruction task. We found that sensitivity to both global and phonemic similarity increased over time, but with global sensitivity reaching adult levels early on in development. In Chapter 5 a neural network was trained on the mappings between real acoustic input and articulatory output data allowing us to simulate the development of phonological representations computationally. The simulation data provide further evidence of a developmental increase in sensitivity to both global and phonemic similarity within a preliterate model. Taken together, the results provide strong evidence that as children’s vocabularies grow they become increasingly sensitive to both the global properties and segmental structure of words, independent of literacy experience. Children’s explicit awareness of phonemes, on the other hand, seems to emerge as a consequence of learning the correspondence between letters and sounds. Within the context of the wider literature, the current results are most consistent with the PRIMIR framework which predicts early detailed phonetic representations alongside gradually emerging phonemic categories (Werker & Curtin, 2005). This thesis underlines the importance of using implicit measures when trying to probe the representations themselves rather than children’s conscious awareness of them. The thesis also represents an important step towards modelling the emergence of segmental representation computationally using real speech data.

This study investigated whether or not variability in the severity of speech sound disorders is related to variability in phonological short-term memory and/or variability in the accuracy of phonological representations. The aim was to determine speech processing predictors of severity of speech sound disorders. A total of 33 children, aged three to six years of age, were assessed on measures of nonword repetition, accuracy of phonological representations, accuracy of speech production, and language. The tests administered included the Clinical Evaluation of Language Fundamentals Preschool – 2 Australian, the Diagnostic Evaluation of Articulation and Phonology, the Nonword Repetition Test (modified), and the Phonological Representation Judgement Task (modified). The relationships between the results of these tests were established using a correlation analysis. The relationship between accuracy of phonological representations and the percentage of consonants correct was found to be mediated by language. There was no significant relationship between nonword repetition and percentage consonants correct. These findings may have been the result of small sample size, age of the participants, or co-morbid language difficulties. These findings imply that variability in severity of speech sound disorders may be related to a variable not directly assessed in this study. This variable may be a constraint relating to the stored motor programs within children’s speech processing systems. Implications for future research are discussed.

Få studier finns om små barns fonologiska förmåga relaterat till arbetsminne. Det råder också en brist på test av arbetsminne för små barn. Föreliggande studie syftade därför till att studera relationen mellan visuellt arbetsminne, fonologiskt arbetsminne och förmåga att hantera fonologiska representationer hos treåringar. Detta har gjorts genom att samla in jämförelsedata för treåringars resultat på det nyutvecklade surfplatte-testet KUBEN (Kognitiv utveckling hos små barn), som testar förmågorna visuellt och fonologiskt arbetsminne samt fonologisk diskrimination. Dessutom har test för fonologisk produktion, även det testat med hjälp av surfplatta, och nonordsrepetition använts. I studien deltog 91 treåriga svenska barn med typisk utveckling. För framför allt visuellt arbetsminne, fanns ett mycket litet underlag att jämföra med, men resultatet visade att barngruppen presterade som förväntat vad gäller samtliga testade förmågor. Förmågorna förbättrades med ökad ålder, däremot var kön och vana av surfplatta inte faktorer som påverkade barnens resultat. I resultatet beskrivs också samband mellan förmågorna. Det fanns samband mellan alla de förmågor som i denna studie mäter fonologiska representationer (fonologisk diskrimination, nonordsrepetition och fonologisk produktion). Däremot korrelerade dessa fonologiska förmågor inte med test för fonologiskt arbetsminne, vilket var ett mindre väntat resultat. En möjlig förklaring kan vara att det är svårt att separat testa fonologiskt arbetsminne hos barn så små som tre år. Inget samband förelåg heller mellan test av fonologiskt och visuellt arbetsminne, vilket dock indikerar att två olika arbetsminnesförmågor har testats. Detta styrker den falang inom forskningen som menar att visuellt och fonologiskt arbetsminne är separerade förmågor redan hos små barn. / There are few studies regarding phonological skills related to working memory in young children. There is also a lack of tests of working memory for children in the younger ages. The aim of the current study was therefore to examine the relationship between visual working memory, phonological working memory and the ability to manage phonological representations, in three-year-olds. This was done by collecting comparison data of threeyear- old children’s results on the newly developed tablet-test ”KUBEN” (Cognitive development in young children), which measures the abilities visual and phonological working memory and phonological discrimination. In addition test for phonological production, also tested with tablet, and nonword repetition were used. A total of 91 Swedish three-year-old children with typical development participated in the study. For especially visual working memory, there was a lack of material with which to compare, but the result showed that children performed as expected regarding all tested abilities. The abilities improved with increasing age. On the contrary, neither gender nor experience of using tablets, affected the results of the children’s performance. The result of this study further describes relations between the tested abilities. There were correlations between all the abilities in this study that measures phonological representations (phonological discrimination, nonword repetition and phonological production). However, these phonological abilities did not correlate with the test of phonological working memory, which is a less expected finding. A possible explanation may be that it is difficult to test phonological working memory separately in children as young as three years old. Neither was there a correlation between tests of phonological and visual working memory, which indicates that two different abilities of working memory were tested. This confirms the faction within research arguing that visual and phonological working memory are separated abilities, already in young children.

Η εξελικτική δυσλεξία είναι μια ειδική μαθησιακή δυσκολία στην κατάκτηση του γραπτού λόγου που δεν σχετίζεται με χαμηλό νοητικό δυναμικό, ελλιπείς εκπαιδευτικές ευκαιρίες ή κάποιο εμφανές αισθητηριακό ή νευρολογικό πρόβλημα. Σύμφωνα με την «υπόθεση των φωνολογικών αναπαραστάσεων», που έχει υποστηριχθεί από δεδομένα στην αγγλική γλώσσα, τα άτομα με δυσλεξία παρουσιάζουν δυσκολία στην επαρκή αποθήκευση και ανάσυρση ακολουθιών ήχων που απαρτίζουν λέξεις, δηλαδή στη διαμόρφωση επαρκών «φωνολογικών αναπαραστάσεων». Στην παρούσα εργασία εξετάστηκε συστηματικά η παραπάνω υπόθεση. Δύο ομάδες 25 (επιλεγμένων από την κοινή τάξη) και 20 (με επίσημη διάγνωση από το ΚΕΔΔΥ) δυσλεξικών μαθητών εξετάστηκαν παράλληλα με δύο ομάδες ελεγχου: η πρώτη ίδιας χρονολογικής ηλικίας και καλής αναγνωστικής ικανότητας και η δεύτερη μικρότερης χρονολογικής ηλικίας και ανάλογης αναγνωστικής ικανότητας με τους δυσλεξικούς. Διαπιστώθηκαν ήπιες δυσκολίες των δυσλεξικών αναφορικά με την ποιότητα των φωνολογικών τους αναπαραστάσεων, όπως αξιολογήθηκε από την ικανότητά τους στην κατονομασία εικόνων. Από την άλλη, οι συσχετίσεις της επίδοσής τους στην κατονομασία εικόνων με επιδόσεις σε δοκιμασίες επεξεργασίας εξερχόμενης και εισερχόμενης φωνολογικής πληροφορίας, αλλά και φωνολογικής επίγνωσης, βασισμένων μάλιστα στα ίδια στοιχεία του λεξικού με εκείνα που είχαν χρησιμοποιηθεί στη δοκιμασία κατονομασίας εικόνων, δεν ήταν σε όλες τις περιπτώσεις ιδιαίτερα ισχυρές. Πιθανοί αιτιολογικοί παράγοντες για τις δυσκολίες των δυσλεξικών μαθητών στο φωνολογικό επίπεδο διερευνήθηκαν τόσο σε γνωστικό όσο και σε αντιληπτικό επίπεδο. Σε γνωστικό επίπεδο, ο παράγοντας της «συχνότητας» της φωνολογικής αναπαράστασης φάνηκε να σχετίζεται ισχυρότερα με την ποιότητα των φωνολογικών αναπαραστάσεων όλων των μαθητών ανεξάρτητα από το επίπεδο αναγνωστικής ικανότητας, σε σχέση με τον παράγοντα του «αριθμού των συλλαβών». Τέλος, σε αντιληπτικό επίπεδο εξετάστηκαν δύο παράμετροι της ακουστικής αντίληψης ως πιθανοί αιτιολογικοί παράγοντες των δυσκολιών των δυσλεξικών στη φωνολογική επεξεργασία: α. η αντίληψη ταχύτατα παρουσιαζόμενων ακουστικών ερεθισμάτων (Tallal) και β. η αντίληψη του κέντρου του ακουστικού ερεθίσματος (p-center, Goswami). Τα αποτελέσματα δεν φαίνεται να υποστηρίζουν τις υποθέσεις για πιθανά ελλείμματα στις συγκεκριμένες παραμέτρους ακουστικής αντίληψης που εξετάστηκαν. / Developmental dyslexia is a specific learning difficulty in acquiring literacy skills that manifests despite normal IQ, adequate educational opportunity and in the absence of any obvious sensory or neurological damage. According to the “Phonological Representations Hypothesis”, a hypothesis that has been supported by research in English, a core deficit for individuals with dyslexia is a difficulty in accurately storing and retrieving the sound sequences that make up words, or “phonological representations”. In this thesis the “Phonological Representations Hypothesis” of dyslexia was tested and elaborated. Two groups of 25 (chosen from normal classes) and 20 (with formal diagnosis from the National Center of Diagnosis, Differential Diagnosis and Educational Support of Greece) dyslexics were assessed alongside chronological age and reading ability matched groups. Mild difficulties of dyslexics were found as far as the quality of the phonological representations is concerned, as indexed by picture naming. Assossiations between performance in picture naming and performance on related input and output phonological processing tasks and phonological awareness taks were not in all cases strong. Possible reasons for dyslxexic’s phonological difficulties were investigated at both cognitive and perceptual levels. As far as the cognitive level is concerned, “frequency” rather than “ length” of the phonological representation was found to be associated more strongly with the quality of the phonological representation of all students independently of their reading ability. As far as the perceptual level is concerned, two different explanatory factors for dyslexic’s difficulties in phonological processing were assessed: a. perception of rapidly presented auditory stimuli (Tallal, 1980) and b. perception of the perceptual center of acoustic signals (p-center, Goswami, 2002). Results are not stronlgy supportive of the two hypotheses tested concerning deficits in parameters of perception of acoustic stimuli.

<p>The general aim of this thesis was to investigate phonological processing skills in dyslexic children and adults and their relation to speech perception. Dyslexia can be studied at various levels: at a biological, cognitive and an environmental level. This thesis mainly looks at environmental and cognitive factors. It is a commonly held view that dyslexia is related to problems with phonological processing, that is, dyslexics have problems dealing with the sound structure of language. The problem is for example seen in tasks where the individual has to manipulate sound segments in the spoken language, read non-words, rapidly name pictures and digits, keep verbal material in short-term memory, and categorize and discriminate sound contrasts in speech perception. To fully understand the dyslexic’s problems we have to investigate both children and adults since the problems might change during the lifespan as a result of changes in the language system and compensatory mechanisms in the poor reader. Research indicates that adult dyslexics can reach functional reading proficiency but still perform poorly on tasks of phonological processing. Even though they can manage many everyday reading situations problems often arise when adult dyslexics enter higher education. The phonological problems of dyslexics are believed to be related to the underlying phonological representations of the language. The phonological representations have been hypothesized to be weakly specified or indistinct and/or not enough segmented. Deviant phonological representations are believed to cause problems when the mapping of written language is to be made to the phonological representations of spoken language during reading acquisition. In Paper 1 adults’ phonological processing and reading habits were investigated in order to increase our understanding of how the reading problems develop into adulthood and what the social consequences are. The results showed that adult dyslexics remained impaired in their phonological processing and that they differed substantially from controls in their choices regarding higher education and also regarding reading habits. Paper 2 reviews research that has used the sine wave speech paradigm in studies of speech perception. The paper also gives a detailed description of how sine wave speech is made and how it can be characterized. Sine wave speech is a course grained description of natural speech lacking phonetic detail. In Paper 3 sine wave speech varying with regard to how much suprasegmental information it contains is employed. Results showed that dyslexics were poorer at identifying monosyllabic words but not disyllabic words and a sentence, plausibly because the dyslexics had problems identifying the phonetic information in monosyllabic words. Paper 4 tested dyslexics’ categorization performance of fricative-vowel syllables and the results showed that dyslexics were less consistent than controls in their categorization indicating poorer sensitivity to phonetic detail. In all the results of the thesis are in line with the phonological deficit hypothesis as revealed by adult data and the performance on task of speech perception. It is concluded that dyslexic children and adults seem to have less well specified phonological representations. </p>

The general aim of this thesis was to investigate phonological processing skills in dyslexic children and adults and their relation to speech perception. Dyslexia can be studied at various levels: at a biological, cognitive and an environmental level. This thesis mainly looks at environmental and cognitive factors. It is a commonly held view that dyslexia is related to problems with phonological processing, that is, dyslexics have problems dealing with the sound structure of language. The problem is for example seen in tasks where the individual has to manipulate sound segments in the spoken language, read non-words, rapidly name pictures and digits, keep verbal material in short-term memory, and categorize and discriminate sound contrasts in speech perception. To fully understand the dyslexic’s problems we have to investigate both children and adults since the problems might change during the lifespan as a result of changes in the language system and compensatory mechanisms in the poor reader. Research indicates that adult dyslexics can reach functional reading proficiency but still perform poorly on tasks of phonological processing. Even though they can manage many everyday reading situations problems often arise when adult dyslexics enter higher education. The phonological problems of dyslexics are believed to be related to the underlying phonological representations of the language. The phonological representations have been hypothesized to be weakly specified or indistinct and/or not enough segmented. Deviant phonological representations are believed to cause problems when the mapping of written language is to be made to the phonological representations of spoken language during reading acquisition. In Paper 1 adults’ phonological processing and reading habits were investigated in order to increase our understanding of how the reading problems develop into adulthood and what the social consequences are. The results showed that adult dyslexics remained impaired in their phonological processing and that they differed substantially from controls in their choices regarding higher education and also regarding reading habits. Paper 2 reviews research that has used the sine wave speech paradigm in studies of speech perception. The paper also gives a detailed description of how sine wave speech is made and how it can be characterized. Sine wave speech is a course grained description of natural speech lacking phonetic detail. In Paper 3 sine wave speech varying with regard to how much suprasegmental information it contains is employed. Results showed that dyslexics were poorer at identifying monosyllabic words but not disyllabic words and a sentence, plausibly because the dyslexics had problems identifying the phonetic information in monosyllabic words. Paper 4 tested dyslexics’ categorization performance of fricative-vowel syllables and the results showed that dyslexics were less consistent than controls in their categorization indicating poorer sensitivity to phonetic detail. In all the results of the thesis are in line with the phonological deficit hypothesis as revealed by adult data and the performance on task of speech perception. It is concluded that dyslexic children and adults seem to have less well specified phonological representations.

Made available in DSpace on 2014-08-20T13:48:03Z (GMT). No. of bitstreams: 1 Marco Antonio Adamoli_Tese.pdf: 5526851 bytes, checksum: 925611790770b0566c88972581441cf7 (MD5) Previous issue date: 2012-12-21 / In this dissertation, I have analyzed the oral and orthographic production of the variable diphthongs [aj] and [ej] in Brazilian Portuguese (BP) by a group of fifteen children who were developing their literacy processes in an Elementary School in Pelotas, RS. My main objective was to describe the oral and written production of such vowel sequences and, based on comparisons found in the collected material, to provide arguments not only for the discussion about the phonological representation of those sequences but also for the proposal of child representation restructuring based on how they learn to write. In order to achieve this objective, I presupposed that children‟s oral production and their early orthographic productions of the diphthongs under investigation, collected for two years in a row, could provide clues to comprehend these children‟s phonological knowledge of those vowel sequences. Data analysis showed that, regarding oral production, the first graders produced very low frequencies around 5% - of both diphthongs whereas second graders yielded 63% for [aj] and 44% for [ej]. Concerning orthographic productions, data analysis showed that, at the beginning of their literacy processes, children tend to have some difficulties regarding conventional writing in terms of spelling both vowel groups since they prefer forms without the semivowel. Besides, in subsequent stages, an important change was perceived in the children‟s orthographic development: around 80% for the production of the grapheme i‟, which seems to evidence that these orthographic structures have already been acquired by second graders. On the whole, the data, along with further arguments regarding the diphthongs in variation and oral acquisition, provided arguments to make me suggest that children spell such segments as if they had one vowel only in the subjacency, /a/ and /e/, in accordance with the input they got, rather than as a structure vowel + glide, which would be produced in the following stages, when they learn how to write. This interpretative proposal is supported by the fact that children are acquiring the phonology of their language in a successive process of (re)construction of their phonological representations while their orthographic systems are being built. Based on the data collected by this study and a set of data on the acquisition of such segments, I questioned whether palatal fricatives are complex segments in child phonology and proposed an interpretation for the utterance of the phonetic diphthongs [aj] and [ej] which says that the children under study interpreted the palatal fricative consonants, in their early phonological development, as simple segments and modified their interpretation due to the learning of the alphabet writing. / Nesta tese, analisamos as produções orais e ortográficas dos ditongos variáveis [aj] e [ej] do PB de um grupo composto por quinze crianças em fase de alfabetização, pertencentes a uma escola de ensino fundamental da cidade de Pelotas/RS. Tivemos como objetivo principal descrever a produção oral e escrita de tais sequências vocálicas e, a partir da comparação do material empírico obtido, fornecer argumentos à discussão sobre a representação fonológica de tais sequências vocálicas, bem como à proposta de reestruturação das representações infantis a partir da aprendizagem da escrita. A fim de atender a esse objetivo, partimos do pressuposto de que as produções orais infantis e as primeiras produções ortográficas dos ditongos em foco, coletados em um período de dois anos consecutivos, pudessem oferecer-nos indícios para a compreensão do conhecimento fonológico desse grupo de crianças sobre tais sequências vocálicas. O levantamento dos dados mostrou-nos que, quanto às produções orais, as crianças concluíram o primeiro ano produzindo frequências muito baixas desses dois ditongos, próximas a 5%, ao passo que, ao final do segundo ano de escolarização, os percentuais chegaram a 63%, para [aj], e 44%, para [ej]. Em relação às produções ortográficas, o levantamento dos dados revelou-nos que, no início da escolarização, as crianças tendem a apresentar dificuldades quanto à escrita convencional no que diz respeito à grafia desses dois grupos vocálicos, preferindo formas sem a semivogal, e que, em estágios subsequentes, uma mudança importante no desenvolvimento ortográfico das crianças é percebida, pois constatamos índices em torno de 80% de produção do grafema i‟, o que parece indicar que essas estruturas ortográficas são adquiridas pelas crianças já a partir do segundo ano. Em seu conjunto, os dados coletados, somados a outros argumentos adicionais também sobre os ditongos na variação e na aquisição oral, forneceram argumentos para sugerirmos que as crianças grafam tais segmentos considerando-os como portadores de uma vogal apenas na subjacência, /a/ e /e/, dadas as informações percebidas pelo input, e não como uma estrutura do tipo vogal + glide, a qual viria a surgir em estágios posteriores, por meio da aprendizagem da escrita. Essa proposta interpretativa tem como apoio o fato de a criança estar adquirindo a fonologia de sua língua, em um processo sucessivo de (re) construção de suas representações fonológicas, ao mesmo tempo em que o seu sistema ortográfico passa a ser construído. Com base nos dados deste estudo e em um conjunto de dados de aquisição sobre tais grupos vocálicos, questionamos a proposta de serem as fricativas palatais segmentos complexos na fonologia infantil e propusemos uma interpretação para o surgimento dos ditongos fonéticos [aj] e [ej] segundo a qual as crianças investigadas interpretam as consoantes fricativas palatais, em etapa do desenvolvimento fonológico inicial, como segmentos simples, tendo sua interpretação modificada em decorrência da aprendizagem da escrita alfabética.