Influence of consonantal context on the reading of vowels: Evidence from children

Revisiting the definition of dyslexia

The International Dyslexia Association definition of dyslexia was updated 20 years ago and has been referenced frequently in research and practice. In this paper, researchers from the Florida Center for Reading Research consider the components of the definition and make recommendations for revisions. These include recognizing the persistence of word-reading, decoding, and spelling difficulties, acknowledging the multifactorial causal basis of dyslexia, clarifying exclusionary factors, and denoting comorbidity with other developmental disorders. It is also suggested that the academic and psychosocial consequences of dyslexia be highlighted to reinforce a preventive service delivery model. Lastly, the inclusion of dyslexia within a specific learning disability category is supported.

The English Sublexical Toolkit: Methods for indexing sound-spelling consistency

This work introduces the English Sublexical Toolkit, a suite of tools that utilizes an experience-dependent learning framework of sublexical knowledge to extract regularities from the English lexicon. The Toolkit quantifies the empirical regularity of sublexical units in both the reading and spelling directions (i.e., grapheme-to-phoneme and phoneme-to-grapheme) and at multiple grain sizes (i.e., phoneme/grapheme and onset/rime unit size). It can extract multiple experience-dependent regularity indices for words or pseudowords, including both frequency indices (e.g., grapheme frequency) and conditional probability indices (e.g., grapheme-to-phoneme probability). These tools provide (1) superior estimates of the regularities that better reflect the complexity of the sublexical system relative to previously published indices and (2) completely novel indices of sublexical units such as phonographeme frequency (i.e., combined units of individual phonemes and graphemes that are independent of processing direction). We demonstrate that measures from the toolkit explain significant amounts of variance in empirical data (naming of real words and lexical decision), and either outperform or are comparable to the best available consistency measures. The flexibility of the toolkit is further demonstrated by its ability to readily index the probability of different pseudowords pronunciations, and we report that the measures account for the majority of variance in these empirically observed probabilities. Overall, this work provides a framework and resources that can be flexibly used to identify optimal corpus-based consistency measures that help explain reading/spelling behaviors for real and pseudowords.

Pronunciation of Vowel Digraphs in Nonwords: A Replication and Extension

In English, the pronunciation of a vowel digraph can vary; for example, ea is pronounced /ɛ/ in bread but /i/ in beach and /eɪ/ in break. We investigated participant-level effects on the pronunciation of ambiguous vowel digraphs in nonwords (e.g., yeath) using standardized test measures of six reading-related skills in 80 young adults. We employed both an established written task and set of nonword stimuli and a spoken version of the task with the same stimuli. We largely replicated the previously reported pattern of preferred nonword pronunciations in both the written and spoken versions of the task. Generalized linear mixed-effects model analyses revealed that individual differences in phonological memory, spelling knowledge, and word reading efficiency contributed to pronunciation choice beyond item-level effects. Overall, taken together with the results of item-level analyses, our findings are consistent with models and theories in which specific reading-related skills, intralexical context, and interlexical pronunciation knowledge influence ambiguous vowel digraph pronunciation in nonword reading in fluently reading young adults.

Orthography-phonology consistency in English: Theory- and data-driven measures and their impact on auditory vs. visual word recognition

Research on orthographic consistency in English words has selectively identified different sub-syllabic units in isolation (grapheme, onset, vowel, coda, rime), yet there is no comprehensive assessment of how these measures affect word identification when taken together. To study which aspects of consistency are more psychologically relevant, we investigated their independent and composite effects on human reading behavior using large-scale databases. Study 1 found effects on adults' naming responses of both feedforward consistency (orthography to phonology) and feedback consistency (phonology to orthography). Study 2 found feedback but no feedforward consistency effects on visual and auditory lexical decision tasks, with the best predictor being a composite measure of consistency across grapheme, rime, OVC, and word-initial letter-phoneme. In Study 3, we explicitly modeled the reading process with forward and backward flow in a bidirectionally connected neural network. The model captured latent dimensions of quasi-regular mapping that explain additional variance in human reading and spelling behavior, compared to the established measures. Together, the results suggest interactive activation between phonological and orthographic word representations. They also validate the role of computational analyses of language to better understand how print maps to sound, and what properties of natural language affect reading complexity.

Set for Variability as a Critical Predictor of Word Reading: Potential Implications for Early Identification and Treatment of Dyslexia

Quasiregular orthographies such as English contain substantial ambiguities between orthography and phonology that force developing readers to acquire flexibility during decoding of unfamiliar words, a skill referred to as a "set for variability" (SfV). The ease with which a child can disambiguate the mismatch between the decoded form of a word and its actual lexical phonological form has been operationalized using the SfV mispronunciation task (e.g., the word wasp is pronounced to rhyme with clasp [i.e., /wæsp/] and the child must recognize the actual pronunciation of the word to be /wɒsp/). SfV has been shown to be a significant predictor of word reading variance. However, little is known about the relative strength of SfV as a predictor of word reading compared to other well-established predictors or the strength of this relationship in children with dyslexia. To address these questions, we administered the SfV task to a sample of grade 2-5 children (N=489) along with other reading related measures. SfV accounted for 15% unique variance in word reading above and beyond other predictors, whereas phonological awareness (PA) accounted for only 1%. Dominance analysis indicated SfV is the most powerful predictor, demonstrating complete statistical dominance over other variables including PA. Quantile regression revealed SfV is a stronger predictor at lower levels of reading skill, indicating it may be an important predictor in students with dyslexia. Results suggest that SfV is a powerful and potentially highly sensitive predictor of early reading difficulties and, therefore, may be important for early identification and treatment of dyslexia.

Number and Syllabification of Following Consonants Influence Use of Long Versus Short Vowels in English Disyllables

Spelling-to-sound translation in English is particularly complex for vowels. For example, the pronunciations of ‹a› include the long vowel of ‹paper› and ‹sacred› and the short vowel of ‹cactus› and ‹happy›. We examined the factors that are associated with use of long versus short vowels by conducting analyses of English disyllabic words with single medial consonants and consonant sequences and three behavioral studies in which a total of 119 university students pronounced nonwords with these structures. The vocabulary analyses show that both the number of medial consonants and their syllabification influence vowel length. Participants were influenced by these aspects of context, some of which are not explicitly taught as a part of reading instruction. Although these results point to implicit statistical learning, participants produced fewer long vowels before single medial consonants than anticipated based on our vocabulary statistics for spelling-to-sound correspondences in disyllabic words. Participants also produced more long vowels before two identical consonant letters than anticipated given these statistics. We consider the reasons for these outcomes, and we also use the behavioral data to test two models of spelling-to-sound translation.

Developmental Dyslexia, Reading Acquisition, and Statistical Learning: A Sceptic's Guide

Many theories have been put forward that propose that developmental dyslexia is caused by low-level neural, cognitive, or perceptual deficits. For example, statistical learning is a cognitive mechanism that allows the learner to detect a probabilistic pattern in a stream of stimuli and to generalise the knowledge of this pattern to similar stimuli. The link between statistical learning and reading ability is indirect, with intermediate skills, such as knowledge of frequently co-occurring letters, likely being causally dependent on statistical learning skills and, in turn, causing individual variation in reading ability. We discuss theoretical issues regarding what a link between statistical learning and reading ability actually means and review the evidence for such a deficit. We then describe and simulate the "noisy chain hypothesis", where each intermediary link between a proposed cause and the end-state of reading ability reduces the correlation coefficient between the low-level deficit and the end-state outcome of reading. We draw the following conclusions: (1) Empirically, there is evidence for a correlation between statistical learning ability and reading ability, but there is no evidence to suggest that this relationship is causal, (2) theoretically, focussing on a complete causal chain between a distal cause and developmental dyslexia, rather than the two endpoints of the distal cause and reading ability only, is necessary for understanding the underlying processes, (3) statistically, the indirect nature of the link between statistical learning and reading ability means that the magnitude of the correlation is diluted by other influencing variables, yielding most studies to date underpowered, and (4) practically, it is unclear what can be gained from invoking the concept of statistical learning in teaching children to read.

Initial validation of a measure of decoding difficulty as a unique predictor of miscues and passage reading fluency

Quantifying the decoding difficulty (i.e., 'decodability') of text is important for accurately matching young readers to appropriate text and scaffolding reading development. Since no easily accessible, quantitative, word-level metric of decodability exists, we developed a decoding measure (DM) that can be calculated via a web-based scoring application that takes into account sub-lexical components (e.g. orthographic complexity), thus measuring decodability at the grapheme-phoneme level, which can be used to judge decodability of individual words or passages. Here we report three experiments using the DM: two predicting children's word-level errors and one predicting passage reading fluency. Generalized linear mixed effect models showed that metrics from the DM explained unique variance in children's oral reading miscues after controlling for word frequency in two samples of children (experiments 1 and 2), and that more errors were made on words with higher DM scores for poor readers. Furthermore, the DM metrics predicted children's number of words read correctly per minute after accounting for estimated Lexile passage scores in a third sample (experiment 3). These results show that after controlling for word frequency (experiments 1 and 2) and estimated Lexile scores (experiment 3) the model including the DM metrics was significantly better in predicting children's word reading fluency both for individual words and passages. While further refinement of this DM measure is ongoing, it appears to be a promising new measure of decodability at both the word and passage level. The measure also provides the opportunity to enable precision teaching techniques, as grapheme-phoneme correspondence profiles unique to each child could facilitate individualized instruction, and text.

How the Science of Reading Informs 21st-Century Education

The science of reading should be informed by an evolving evidence base built upon the scientific method. Decades of basic research and randomized controlled trials of interventions and instructional routines have formed a substantial evidence base to guide best practices in reading instruction, reading intervention, and the early identification of at-risk readers. The recent resurfacing of questions about what constitutes the science of reading is leading to misinformation in the public space that may be viewed by educational stakeholders as merely differences of opinion among scientists. Our goals in this paper are to revisit the science of reading through an epistemological lens to clarify what constitutes evidence in the science of reading and to offer a critical evaluation of the evidence provided by the science of reading. To this end, we summarize those things that we believe have compelling evidence, promising evidence, or a lack of compelling evidence. We conclude with a discussion of areas of focus that we believe will advance the science of reading to meet the needs of all children in the 21st century.

Variations in the use of simple and context-sensitive grapheme-phoneme correspondences in English and German developing readers

Learning to read in most alphabetic orthographies requires not only the acquisition of simple grapheme-phoneme correspondences (GPCs) but also the acquisition of context-sensitive GPCs, where surrounding letters change a grapheme's pronunciation. We aimed to explore the use and development of simple GPCs (e.g. a ➔ /æ/) and context-sensitive GPCs (e.g. [w]a ➔ /ɔ/, as in "swan" or a[l][d] ➔ /o:/, as in "bald") in pseudoword reading. Across three experiments, English- and German-speaking children in grades 2-4 read aloud pseudowords, where vowel graphemes had different pronunciations according to different contexts (e.g. "hact", "wact", "hald"). First, we found that children use context-sensitive GPCs from grade 2 onwards, even when they are not explicitly taught. Second, we used a mathematical optimisation procedure to assess whether children's vowel responses can be described by assuming that they rely on a mix of simple and context-sensitive GPCs. While the approach works well for German adults (Schmalz et al. in Journal of Cognitive Psychology, 26, 831-852, 2014), we found poor model fits for both German- and English-speaking children. Additional analyses using an entropy measure and data from a third experiment showed that children's pseudoword reading responses are variable and likely affected by random noise. We found a decrease in entropy across grade and reading ability across all conditions in both languages. This suggests that GPC knowledge becomes increasingly refined across grades 2-4.

Consistency norms for 37,677 english words

Consistency reflects the mapping between spelling and sound. That is, a word is feedforward consistent if its pronunciation matches that of similarly spelled words, and feedback consistent if its spelling matches that of similar pronounced words. For a quasi-regular language such as English, the study of consistency effects on lexical processing has been limited by the lack of readily accessible norms. In order to improve current methodological resources, feedforward (spelling-to-sound) and feedback (sound-to-spelling) consistency measures for 37,677 English words were computed. The consistency measures developed here are operationalized at the composite level for multisyllabic words, and at different sub-syllabic segments (onset, nucleus, coda, oncleus, and rime) for both monosyllabic and multisyllabic words. These measures constitute the largest database of English consistency norms to be developed, and will be a valuable resource for researchers to explore the effects of consistency on lexical processes, such as word recognition and spelling. The norms are available as supplementary material with this paper.

Technology-Based Tools for English Literacy Intervention: Examining Intervention Grain Size and Individual Differences

Technology plays an increasingly important role in educational practice, including interventions for struggling learners (Torgesen et al., 2010; de Souza et al., 2018). This study focuses on the efficacy of tablet-based applications (see Word Reading, Grapholearn, and an experimental word-level program) for the purpose of supplementing early English literacy intervention with primary grades 1 and 2 children. The children were identified for learning support programs within Singaporean schools, which follow a bilingual policy, meaning children were learning reading in English plus an additional language. One hundred forty-seven children across seven schools participated (Mean age = 6.66). Within learning support classrooms, triplets of students matched on basic reading skills were randomly assigned to one of three groups: (1) phoneme-level, (2) rime-level, or (3) word-level focused interventions. All groups performed reading skills activities on iPads, across two phases over a 14-week period. Assessments for word reading accuracy and fluency, pseudoword decoding accuracy and fluency, and spelling were administered at four time points, pre- and post-intervention. Additional baseline measures were taken to assess individual differences in phonological awareness, orthographic awareness, general cognitive ability, statistical learning, and bilingual vocabulary knowledge. Mixed model analysis was conducted on the pre- to post-test measures across the two phases of the intervention (focused on accuracy then fluency). All groups made gains across the different literacy measures, while the phoneme-level intervention showed an advantage over the rime-level intervention, but not the word-level intervention, for decoding. There were also moderating effects of individual differences on outcomes. The general pattern of results showed an advantage of the word-level intervention for those with poorer phonological awareness for reading fluency; and a phoneme-level intervention advantage for those with poorer statistical learning ability. Children's bilingual group (English plus Mandarin, English plus Malay, or English plus Tamil) also showed differential effects of the type of intervention (e.g., phoneme- or word-level) on different outcome measures. These results, along with data collected from the tablets during the intervention, suggest the need to examine the interplay between different types of technology-based interventions and individual differences in learning profiles.

Linking Behavioral and Computational Approaches to Better Understand Variant Vowel Pronunciations in Developing Readers

The overarching goal of the new Florida State University/Haskins Laboratory/University of Connecticut Learning Disability (LD) Hub project is to align computational and behavioral theories of individual word reading development more closely with the challenges of learning to read a quasi-regular orthography (i.e., English) for both typically developing (TD) children and, more specifically, children with dyslexia. Our LD Hub adopts an integrated approach to better understand the neurocognitive bases of individual differences in word reading development by specifically examining the experiential (exogenous) and child-specific (endogenous) factors that determine acquisition of orthographic-phonological knowledge at different subword granularities using behavioral and computational modeling. Findings are intended to enrich understanding of the processes that influence individual differences in word reading development in TD and dyslexic children and significantly inform issues of practice (e.g., curriculum, instruction, diagnosis, and intervention). Here, we briefly provide the rationale for the Hub and present findings from the initial behavioral and computational modeling studies.

Development of context-sensitive pronunciation in reading: The case of ‹c› and ‹g›

Writing systems sometimes deviate from one-to-one associations between letters and phonemes, but the deviations are often predictable from sublexical context. For initial ‹c› and ‹g› in English, deviations from the typical /k/ and /g/ pronunciations are influenced by adjacent context (the following vowel, as in center vs. canter) and nonadjacent context (the presence of a Latinate vs. basic suffix, as in gigantic vs. giggling). We conducted two experiments with participants ranging in reading level from early elementary school to university to study the development of context use. Experiment 1 focused on adjacent context, and Experiment 2 also examined nonadjacent context. Use of context developed slowly, and readers at all levels were not as influenced by it as would be expected given the contextual effects in the English vocabulary. We discuss possible reasons for these phenomena and the need to teach children to use context more effectively.

Development and Prediction of Context-Dependent Vowel Pronunciation in Elementary Readers

As children learn to read they become sensitive to context-dependent vowel pronunciations in words, considered a form of statistical learning. The work of Treiman and colleagues demonstrated that readers' vowel pronunciations depend on the consonantal context in which the vowel occurs and reading experience. We examined child- and nonword-factors associated with children's assignment of more vs. less frequent grapheme-phoneme correspondences (GPC) to vowel pronunciations as a function of rime coda in monosyllabic nonwords. Students (N=96) in grades 2-5 read nonwords in which more vs. less frequent vowel GPCs were wholly supported or partially favored by the rime unit. Two explanatory item-response models were developed using alternative nonword scoring procedures. Use of less frequent vowel GPCs was predicted by set for variability, word reading, and rime support for the context-dependent vowel pronunciation. We interpret the results within a developmental word reading model in which initially incomplete and oversimplified GPC representations become more context-dependent with reading experience.

Statistical learning and dyslexia: a systematic review

The existing literature on developmental dyslexia (hereafter: dyslexia) often focuses on isolating cognitive skills which differ across dyslexic and control participants. Among potential correlates, previous research has studied group differences between dyslexic and control participants in performance on statistical learning tasks. A statistical learning deficit has been proposed to be a potential cause and/or a marker effect for early detection of dyslexia. It is therefore of practical importance to evaluate the evidence for a group difference. From a theoretical perspective, such a group difference would provide information about the causal chain from statistical learning to reading acquisition. We provide a systematic review of the literature on such a group difference. We conclude that there is insufficient high-quality data to draw conclusions about the presence or absence of an effect.

Towards a Theory of Variation in the Organization of the Word Reading System

The strategy underlying most computational models of word reading is to specify the organization of the reading system-its architecture and the processes and representations it employs-and to demonstrate that this organization would give rise to the behavior observed in word reading tasks. This approach fails to adequately address the variation in reading behavior observed across and within linguistic communities. Only computational models that incorporate learning can fully account for variation in organization. However, even extant learning models (e.g., the triangle model) must be extended if they are to fully account for variation in organization. The challenges associated with extending theories in this way are discussed.

Statistical Learning, Letter Reversals, and Reading

Reversal errors play a prominent role in theories of reading disability. We examined reversal errors in the writing of letters by 5-6-year-old children. Of the 130 children, 92 had a history of difficulty in producing speech sounds, a risk factor for reading problems. Children were more likely to reverse letter forms that face left, such as 〈d〉 and 〈J〉, than forms that face right, such as 〈b〉 and 〈C〉. We propose that this asymmetry reflects statistical learning: Children implicitly learn that the right-facing pattern is more typical of Latin letters. The degree of asymmetry that a child showed was not related to the child's reading skill at Time 2, 2 ¾ years later. Although children who went on to become poorer readers made more errors in the letter writing task than children who went on to become better readers, they were no more likely to make reversal errors.

Linguistic pattern analysis of misspellings of typically developing writers in grades 1-9

PURPOSE

A mixed-methods approach, evaluating triple word-form theory, was used to describe linguistic patterns of misspellings.

METHOD

Spelling errors were taken from narrative and expository writing samples provided by 888 typically developing students in Grades 1-9. Errors were coded by category (phonological, orthographic, and morphological) and specific linguistic feature affected. Grade-level effects were analyzed with trend analysis. Qualitative analyses determined frequent error types and how use of specific linguistic features varied across grades.

RESULTS

Phonological, orthographic, and morphological errors were noted across all grades, but orthographic errors predominated. Linear trends revealed developmental shifts in error proportions for the orthographic and morphological categories between Grades 4 and 5. Similar error types were noted across age groups, but the nature of linguistic feature error changed with age.

CONCLUSIONS

Triple word-form theory was supported. By Grade 1, orthographic errors predominated, and phonological and morphological error patterns were evident. Morphological errors increased in relative frequency in older students, probably due to a combination of word-formation issues and vocabulary growth. These patterns suggest that normal spelling development reflects nonlinear growth and that it takes a long time to develop a robust orthographic lexicon that coordinates phonology, orthography, and morphology and supports word-specific, conventional spelling.

Simulating Language-specific and Language-general Effects in a Statistical Learning Model of Chinese Reading

Many theoretical models of reading assume that different writing systems require different processing assumptions. For example, it is often claimed that print-to-sound mappings in Chinese are not represented or processed sub-lexically. We present a connectionist model that learns the print to sound mappings of Chinese characters using the same functional architecture and learning rules that have been applied to English. The model predicts an interaction between item frequency and print-to-sound consistency analogous to what has been found for English, as well as a language-specific regularity effect particular to Chinese. Behavioral naming experiments using the same test items as the model confirmed these predictions. Corpus properties and the analyses of internal representations that evolved over training revealed that the model was able to capitalize on information in "phonetic components" - sub-lexical structures of variable size that convey probabilistic information about pronunciation. The results suggest that adult reading performance across very different writing systems may be explained as the result of applying the same learning mechanisms to the particular input statistics of writing systems shaped by both culture and the exigencies of communicating spoken language in a visual medium.

Is a "Phoenician" reading style superior to a "Chinese" reading style? Evidence from fourth graders

This study compared normally achieving fourth-grade "Phoenician" readers, who identify nonwords significantly more accurately than they do exception words, with "Chinese" readers, who show the reverse pattern. Phoenician readers scored lower than Chinese readers on word identification, exception word reading, orthographic choice, spelling, reading comprehension, and verbal ability. When compared with normally achieving children who read nonwords and exception words equally well, Chinese readers scored as well as these children on word identification, regular word reading, orthographic choice, spelling, reading comprehension, phonological sensitivity, and verbal ability and scored better on exception word reading. Chinese readers also used rhyme-based analogies to read nonwords derived from high-frequency exception words just as often as did these children. As predicted, Phoenician and Chinese readers adopted somewhat different strategies in reading ambiguous nonwords constructed by analogy to high-frequency exception words. Phoenician readers were more likely than Chinese readers to read ambiguous monosyllabic nonwords via context-free grapheme-phoneme correspondences and were less likely to read disyllabic nonwords by analogy to high-frequency analogues. Although the Chinese reading style was more common than the Phoenician style in normally achieving fourth graders, there were similar numbers of poor readers with phonological dyslexia (identifying nonwords significantly more accurately than exception words) and surface dyslexia (showing the reverse pattern), although surface dyslexia was more common in the severely disabled readers. However, few of the poor readers showed pure patterns of phonological or surface dyslexia.