Blog

25-July-2025

DYSLEXIA AND PHONOLOGICAL AWARENESS: DISABILITY OR DEFICIENCY?

A Literature Review

There is lingering debate on the nature of reading disabilities in the U.S.  Research abounds within the medical/scientific domain due to literary interventions within the educational setting.  However, a careful analysis of the data and discussion will benefit further inquiry and understanding of both the nature of reading disabilities and necessary instructional interventions.  Dyslexia, specifically, will be the focus of this review as it relates to literacy and learning. A guiding question for this review is, “Are educational leaders misdiagnosing dyslexia for phonics learning gaps?” A secondary question is, “What are some ways teachers, SpED instructors, and parents can identify those students who are truly dyslexic versus those who may require more support in decoding, or in other early reading skills?” These questions guide the selection, review, analysis, and interpretation of research and discussion gathered in the past decade. 

Why is this topic selected as the focus for this review?  In surveying numerous journals, peer-reviewed papers, books, and research on phonological awareness, dyslexia, and reading intervention, though many differ on the causation and remediation of dyslexia, it is apparent that they all tend to agree on the prevalence of reading deficiencies among today’s children.  In fact, over 60% of children in America fail to meet reading proficiency standards.  While there are several factors that come into play regarding this alarming statistic, such as poor early language development, inadequate instruction, limited reading practice, minimal background knowledge, or a reading disability, for some children, a specific learning disability called dyslexia is the key player as the most common learning disability.  Dyslexia is present to some extent in about 20% of children.  

Consequently, researchers and educational leaders studied, analyzed, and discussed data in recent years related to literacy and learning.  While much research highlights specific characteristics, functions, and efficacy of reading instruction, not all studies agree on preparedness, intervention, or delineation concerning reading development.  This requires a close analysis of the history of dyslexia, reading instructional practices, and collected data on literacy development in children, particularly among children in the early literacy stages.  The guiding question concerning the misdiagnosis of dyslexia for phonics learning gaps will direct the survey and analysis of the data and discussion surrounding reading instruction and disability in education today.  

The process for this literature review is as follows.  First, a careful survey of relevant terms related to dyslexia and phonological awareness will be defined and described, as well as the important points of discussion addressed throughout the collected sources.  Second, the literature will be organized and distinguished between those that discuss dyslexia and those that center on reading development and phonological awareness.  Third, the sources will be analyzed as a whole by comparing the points of agreement and contrasting the points of disagreement.  Common themes along with research gaps will be noted with remaining questions that will call for further research.

The central purpose of this review is to analyze and reflect on research within the field of educational literacy while addressing lingering questions that remain unanswered.  What are the indicators of reading disabilities?  Is dyslexia as prevalent as instructors and specialists presently believe?  Are there instructional practices that must be altered in order to sufficiently meet the needs of language development in children?  Can those children with a genetic predisposition for dyslexia be shielded from disability with explicit and systematic phonics instruction?  How can parents, educators, specialists, and even children themselves be adequately equipped with a thorough understanding on the nature of literacy and language acquisition at the foundational level before being flagged for a disability?  These questions serve as markers for this review and will function as points of discussion throughout the analysis of the literature.  Some goals for the review are to determine commonalities between the sources, distinguish points of disagreement, address outliers from the research, and note gaps within the literature that call for further study and discussion on dyslexia and reading instruction.  

While examining the sources, the overarching response to the findings is that there remain many questions left unanswered regarding the nature, causation, and remediation of dyslexia.  But more than that, limited research exists regarding connections between dyslexia and inadequate reading instruction, particularly concerning phonics.  A close analysis of the literature gathered from recent years will aid in understanding how educators address reading disabilities and what steps are taken to ensure adequate reading preparedness in today’s children.  

Many scholarly articles target a specific issue related to dyslexia, but not all inform readers on the history of dyslexia and its origins in academic research.  Suzanne Adolf and Tiffany Hogan contributed to the Journal of Language, Speech, and Hearing Services in Schools with “Understanding Dyslexia in the Context of Developmental Language Disorders” by focusing on the language basis of dyslexia from both historical and theoretical perspectives.  They acknowledge the lack of consensus on dyslexia as having precise diagnostic criteria even though most people are aware of dyslexia as a generalized reading disorder.  The term is used in a broad sense covering a wide range of difficulties ranging from neurodevelopmental syndromes 

to language delays due to head trauma.  The inclusionary nature of dyslexia in modern research creates confusion, which Adolf and Hogan argue stems from misperceptions about the oral language abilities of children with dyslexia.  They address how dyslexia was first introduced by William Berlin in 1887 as a way to describe adult patients who had reading difficulties caused by a cerebral disease.  Dyslexia came to be understood as a language-based disorder rather than a visually-based disorder.  In the years following William Berlin identifying dyslexia as a language-based disorder, some proposed the idea of “word blindness,” which categorized dyslexia in the visual domain rather than as a phonological processing deficiency.  Through careful research in their literature review, Adolf and Hogan determined from the historical perspective that dyslexia is defined as a difficulty with word level reading and spelling skills that are caused by phonological deficiencies (Adolf & Hogan, 2018).

Historically, various theories considered dyslexia as a perceptual problem.  Dr. Linda S. Siegal noted the common belief embraced by many even today that the defining symptom of dyslexia was writing letters and words backwards.  However, this idea has been discredited in recent years as scientists determined that dyslexia is not a visual issue. Siegal’s work addresses the “dual route theory” of dyslexia, which is a theory that recognizes two mechanisms that individuals use to read words.  These two mechanisms are the direct (orthographic) route and the indirect (phonological) route.  The direct route involves looking at a word and knowing what it says automatically, whereas the indirect route involves translating letters into sounds and knowing the pronunciation of words by the blending of sounds.  It is this indirect route that most dyslexics have difficulty with as they lack phonological skills (Siegel, 2006).

The dyslexia debate centers on the ambiguity of the term.  Throughout the 19th and 20th centuries, theories were proposed and refuted as symptoms of dyslexia manifested themselves differently in different people with some symptoms less apparent in some people than in others.  In “Dyslexia Debated, Then and Now: a Historical Perspective on the Dyslexia Debate,” Philip Kirby compares the history of dyslexia to the history of other hidden disabilities like depression, autism, and ADHD.  Kirby suggests that the difficulty in defining dyslexia stems from its hidden characteristics of cognitive deficiencies (Kirby, 2020).  

Simon J. Gibbs and Julian G. Elliott seem to agree with the challenges of diagnosing dyslexia.  In “The Dyslexia Debate: Life Without the Label,” Gibbs and Elliott address the complexity of the disability and the importance of addressing the needs of all struggling readers without lumping them all under the label “dyslexic.”  They do not reject the existence of dyslexia, but they do consider the widespread use of dyslexia as problematic without scientific validity or function.

In addition to grasping the dyslexia dilemma, a deeper understanding of phonological awareness is imperative in making decisions concerning reading development and disabilities.  In their research on the development of phonological awareness, Jason L. Anthony and David J. Francis acknowledge that the underlying cause of dyslexia is difficulty processing the sounds in one’s language, or “phonological processing.”  This phonological awareness is most strongly connected to literacy and is the greatest predictor of learning to read.  Specifically, phonemic 

awareness, which is the ability to manipulate individual sounds (phonemes) in words, is highly correlated to reading proficiency.  Based on the 2000 National Reading Panel’s report along with research from the past four decades, Anthony and Francis affirm the impact of explicit phonics instruction on reading and spelling, especially on those struggling readers or those at risk for reading difficulties.  Their research on explicit phonics instruction is important for the discussion on dyslexia as dyslexia at its core is a phonological processing disorder.

Interestingly, research shows that there is a prime window for children’s phonological awareness development.  In their study, “The Relationship Between Phonological Awareness and Reading: Implications for the Assessment of Phonological Awareness,” Hogan, Catts, and Little recognize that phonological awareness and letter identification in kindergarten were predictive of children’s reading ability in second grade.  Conversely, word reading in second grade was predictive of children’s phonological awareness in fourth grade.  Hogan, Catts, and Little are speech pathologists who provide an important perspective on reading development, highlighting the reciprocal relationship between phonological awareness and reading development.  In another study, Hogan acknowledged that children with dyslexia are at risk for reading deficits as they have marked deficits in phonological processing.  There is a strong correlation between phonological awareness skills and reading achievement.

With the lingering debate regarding dyslexia, struggling readers, and phonological awareness, there is a need for a closer examination of the research and discussion on educational literacy in America today.  One study on foundational literacy and the home literacy environment aimed to determine if a correlation exists between early literacy development and children with a family-risk of dyslexia.  Lorna G. Hamilton and colleagues conducted a longitudinal study on three-and-a-half-year-olds until they reached nine years of age.  They had a family-risk of dyslexia group, which included those students who had one first-degree relative with dyslexia, and a control group.  The family-risk group did not have any known risk of reading disabilities.  The procedure included storybook exposure and parental literacy instruction.  Parents were asked how often they read to their children and if they taught them to recognize words, read words, and write words.  The researchers found that parents in the control group typically read to their children more often than parents who were in the family-risk group.  It is important to note that the parents reading to their children in the at-risk group were not dyslexic themselves.  The results of this study revealed limited predictors between the home literacy environment and risk for dyslexia, but a correlation was determined between SES and the home literacy environment.  Hamilton attributes this to storybook exposure and parental reading deficiencies.  However, she and her colleagues did not rule out a connection between genetic heritability and parental education/occupation and children’s reading attainment. They concluded that home literacy may be a viable target for early intervention for children with a known family history of dyslexia to support crucial foundational literacy skills to optimize their chances for reading success in school.

In addition to the home literacy environment, other studies explore the physiology of language in children to build understanding on foundational literacy.  While environment 

addresses the nurture aspect of literacy, the brain draws attention to the role of nature.  In their study, “Brain Basis of Phonological Awareness of Spoken Language in Children and its 

Disruption in Dyslexia,” Ioulia Kovelman and her colleagues examined the brain’s role in phonological awareness in young readers.  They used functional magnetic resonance imaging (fMRI) to explore the neural correlates of phonological awareness using auditory language tasks in children who are generally developing readers and children with dyslexia.  Their findings revealed an “under-recruitment” in the left dorsolateral prefrontal cortex in children with dyslexia.  This area of the brain is responsible for working memory and cognitive flexibility.  It is an “important region for goal-directed verbal processing” (Kovelman, et al., 2012).  This finding shows that dyslexia is not related simply to phonological awareness proficiency or reading experiences, but that there is a physiological component involved.  

Generally, this is where the discussion on dyslexia and phonological awareness merge: physiology and language development.  Much of the literature on both sides addresses the brain’s role in literacy.  A recent study highlights the importance of the first year of life for long term language and literacy development.  It revealed that the organization of white matter in the brain in response to environmental stimuli can be observed as early as infancy, where before it could only be seen while children were in formal schooling.  Nadine Gaab, an associate professor at the Harvard Graduate School of Education, along with several researchers found evidence that structural brain networks in infants as young as four months of age are linked to later language and reading skills.  For years, researchers have known that language is related to a child’s brain development while also being shaped by the environment.  Gaab and others agree with this idea while emphasizing the important role the brain plays in identifying language development in children.  This specific study used MRI technology to generate images of white matter pathways in 40 infants, and then five to six years later, Gaab and her colleagues used a variety of literacy assessments to track each child’s development.  They discovered organized white matter in a particular area of the brain in infancy with subsequent oral language and pre-literacy abilities like phonological awareness and vocabulary.  Knowing that this white matter is present in the brain in early infancy should inform instructional practice in multiple ways.  Early identification of language-based learning disabilities, utilizing evidence-based curriculum in preschools and daycare, and support for parents and educators with the research on brain development are all ways that inform instructional practice.  

In addition to research on white matter in the brain and its connection to language development, there is also growing research on dyslexia’s genetic linkage and the importance of early identification and intervention for those with a family history of a reading disability.  Sheryl M. Handler and Walter M. Fierson argue that learning disabilities derive from neurological differences in brain structure and function that impact the brain’s ability to retain, process, or communicate information.  Those diagnosed with dyslexia should receive appropriate support and individualized evidence-based interventions along with psychological, medical, and visual treatments.

In contrast to the research on the physiological component of language development, Suzanne Adlof and Tiffany Hogan affirm that dyslexia is a “language-based disorder,” however, they diverge from the argument that dyslexia is a disorder that is visually-based.  They point out 

a distinct difference between dyslexia, which is a language-based disorder, and a condition known as DLD, developmental language disorder.  The distinction is important to understand, particularly for the purpose of this review.  Dyslexia involves a deficit in word reading, whereas DLD encompasses deficits in overall language development.  Dyslexia is a phonological 

processing disorder, whereas DLD is both a phonological and non-phonological disorder.  Adlof and Hogan discovered from their research that children who had dyslexia and DLD demonstrated poorer vocabulary, sentence repetition, and syntactic comprehension, and they performed poorly on assessments.  Those children who were diagnosed with dyslexia but not DLD performed at a similar level as the control group.  Some even received above average standardized language scores.  Adlof and Hogan emphasize the distinction between dyslexia and DLD even though they are often co-occurring disorders (Adlof, et al., 2018, pp. 762-773).  This is valuable within the educational domain as more children are being diagnosed with dyslexia in the U.S.  There seems to be varying degrees of dyslexia, or DLD, so perhaps there is a prevalence of misdiagnosis of dyslexia for some children who may in fact have DLD, or vice versa.

There is another distinction in the literature between dyslexia as a distinct genetic disorder and as a blanket “catch-all” diagnosis for all reading disabilities.  Tracy Migrants, Janie improved, self-reported assessments on attention or reading decreased.  This means that visual impairment impacts both ADHD and dyslexics, but sometimes convergence insufficiency is the 

stand-alone diagnosis apart from a reading disability.  Migrants, Kiyokawa, and Island acknowledge the need for further investigation on this issue as well as a more holistic approach in the identification, diagnosis, intervention, and treatment of cognitive problems connected to reading and learning.  What is truly an attentional problem from what is a visual convergence 

problem, or a cognitive processing problem?  More research is needed to determine the best way forward.

Certainly, more studies on correctly diagnosing dyslexia are necessary to isolate those students who are truly dyslexic from those who have other challenges. Richard Wagner from Florida State University suggests the use of hybrid models that combine multiple indicators, which will in effect minimize the margin of error. His premise is that the existing definitions of dyslexia do not result in an accurate diagnosis because they usually rely on a single indicator.  Combining multiple indicators to assess reading may provide more clarity and understanding of the nature of the deficiency.  

Invariably, common themes exist between the sources.  The overarching theme is as Dr. Alisha K. Wackerle-Hollman and her colleagues attest: phonological awareness is the strong 

determiner to later reading success.  Another important theme worth noting is the brain’s role in both phonological awareness and reading disabilities. There are brain pathways that support individual differences in learning to read, which Kenneth R. Pugh and colleagues suggest are 

worth examining further to see which networks of the brain best discriminate children with better or worse reading skills.  The research also presents the high demand on reading attention for decoding words.  This is true for dyslexics and non-dyslexics alike.  Andrea Facoetti and colleauges found that dyslexics tend to show lower-level deficits in sensory and attentional processing, and that spatial attention is important for phonological decoding.  This may be why about 25%-40% of dyslexics exhibit criteria for ADHD, and vice versa.  A group of researchers from Italy studied this phenomenon including environmental and genetic factors that may contribute both to developmental dyslexia and ADHD.  They determined that the multiple-deficit model serves as a framework to understand the simultaneous existence of both ADHD and dyslexia in individuals.

Whether dyslexia is misdiagnosed remains to be determined.  The literature selected for this review exposes various indicators of dyslexia as well as the importance of early phonological awareness, however very limited research exists on potential learning gaps associated with a reading disorder diagnosis.  The closest source found that indicates further educational support for young readers is a paper by Jeremy R. Mills from Wright State University and Monica Clarke from Codebreakers LLC. They argue for more teacher training, particularly for those teachers who have dyslexic students.  If teachers are provided training on the early warning signs of dyslexia along with evidence-based interventions to include in classroom instruction, then schools will be equipped to support those students who are struggling readers and will in turn also prevent students from being classified as dyslexic requiring an IEP.  

Future research will provide more understanding on connections between developmental language disorders and phonological awareness.  The literature at present includes causation and remediation of dyslexia with limited information on instructional impact.  Jeremy Mills’ and Monica Clarke’s three-pronged approach, which includes a graduate certification program in the area of dyslexia, a professional development series, as well as a dyslexia center at their university (Wright State), seems to be a way forward.  Collaborative support in education will not only help struggling readers, even those with dyslexia, but all readers.  In this way not only will students receive the training they need, but their teachers as well.  For if all children are expected to read well, then all teachers must be trained to teach well.  

1. Kennedy, Calliope Veludos. (2018). The nature, prevention, and remediation of learning literacy difficulties. Massey University of New Zealand, 1. https://www.dyslexia.com/reports/Veludos-Kennedy-2018.pdf

2.  Handler, Sheryl M. (2016). Dyslexia: what you need to know. Contemporary Pediatrics, 33(8), 18. https://www.proquest.com/openview/690061488e33dedc417095de5585a691/1?pq-origsite=gscholar&cbl=34319

3.  Adolf, S. M., & Hogan, T. P. (2018). Understanding dyslexia in the context of developmental language disorders. Language, Speech, and Hearing Services in Schools, 49(4), 762–773. https://doi.org/10.1044/2018_lshss-dyslc-18-0049 

4.  Siegel, S Linda. (2006). Perspectives on Dyslexia. Paediatrics Child Health, 11(9), 581-587. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2528651/

5. Kirby P. (2020). Dyslexia debated, then and now: a historical perspective on the dyslexia debate. Oxford review of education, 46(4), 472–486. https://doi.org/10.1080/03054985.2020.1747418

6. Gibbs, Simon J., & Elliott, Julian G. (2020). The dyslexia debate: life without the label. Oxford Review of Education, 46(4), 487-500. https://www.tandfonline.com/doi/full/10.1080/03054985.2020.1747419 

7.  Anthony, Jason L., & Francis, David J. (2005).  Development of phonological awareness. Current Directions in Psychological Science, 14, 255-558. https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.525.5413&rep=rep1&type=pdf

8. Hogan, Tiffany P., Catts, Hugh W, & Little, Todd D. (2010). The relationship between phonological awareness and reading: implications for the assessment of phonological awareness. Language, Speech, and Hearing Services in Schools, 36(4), 285-293. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2848754/

9.  Hogan, Tiffany P. et al. (2014). Phonological and lexical influences on phonological awareness in children with specific language impairment and dyslexia. Frontiers in Psychology. (838)5, 1-10. https://www.frontiersin.org/articles/10.3389/fpsyg.2014.00838/full 

10. Hamilton, Lorna G., Hayiou-Thomas, Marianna E., Hulme, Charles, & Snowling, Margaret J. (2016). The home literacy environment as a predictor of the early literacy development of children at family-risk of dyslexia. Scientific Studies of Reading, (20)5, 401-419. https://www.tandfonline.com/doi/full/10.1080/10888438.2016.1213266

11. Kovelman, Ioulia, Norton, Elizabeth S., Christodoulou, Joanna A., Gaab, Nadine, Liberman, Daniel A., Triantafyllou, Christina, Wolf, Maryanne, Whitfield-Gabrieli, Susan, Gabrieli, John D.E. (2012). Brain basis of phonological awareness for spoken language in children and its disruption in dyslexia. Cerebral Cortex (22)4, 754-764. https://academic.oup.com/cercor/article/22/4/754/416751?login=true

12. Zuk, Jennifer, Xi Yu, Sanfilippo, Joseph, Gaab, Nadine. (2021). White matter in infancy is prospectively associated with language outcomes in kindergarten. Developmental Cognitive Neuroscience (50), 1-9. https://www.sciencedirect.com/science/article/pii/S1878929321000645?via%3Dihub

13.  Handler, Sheryl M. & Fierson, Walter M. (2011). Learning disabilities, dyslexia, and vision. Pediatrics (127) 3. https://pediatrics.aappublications.org/content/127/3/e818

14. Adlof, Suzanne M., Hogan, Tiffany P. (2018). 762-773. https://pubs.asha.org/doi/10.1044/2018_LSHSS-DYSLC-18-0049

15. Migrants, Tracy, Kiyokawa, Janie M., & Island, Heide. (2019). The relationship between attention, dyslexia, and convergence insufficiency. International Journal of Undergraduate Research and Creative Activities (11) 1, 1-9. https://pdfs.semanticscholar.org/4b34/d8d38e22874d8e81c0cf0f51a18b50524cb2.pdf

16. Wagner, Richard. (2018). Why is it so difficult to diagnose dyslexia and how can we do better?. International Dyslexia Association (7) 5. ​​https://dyslexiaida.org/why-is-it-so-difficult-to-diagnose-dyslexia-and-how-can-we-do-it-better/.

17. Wackerle-Hollman, Alisha K., Schmitt, Braden A., Bradfield, Tracy A., Rodriguez, Michael C., & McConnell, Scott R. (2015). Redefining individual growth and development indicators: phonological awareness. Journal of Learning Disabilities (48) 5, 495-510. https://files.eric.ed.gov/fulltext/ED605881.pdf

18. Pugh, Kenneth R., Landi, Nicole, Preston, Jonathan L., Mencl, Einar W., Austin, Alison C., Sibley, Daragh, Fulbright, Robert K., Seidenberg, Mark S., Grigorenko, Elena L., Constable, Todd R., Molfese, Peter, & Frost, Stephen J. (2012). The relationship between phonological and auditory processing and brain organization in beginning readers. Brain and Language (125) 2, 173-183. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3417084/

19. Facoetti, Andrea, Trussardi, Anna Noemi, Ruffino, Milena, Lorusso, Maria Luisa, Cattaneo, Carmen, Galli, Rafaella, Molteni, Massimo, Zorzi, Marco. (2010). Multisensory spatial attention deficits are predictive of phonological decoding skills in developmental dyslexia. Journal of Cognitive Neuroscience. (22) 5, 1011-1025. 

20. Mascheretti, Sara, Trezzi, Vittoria, Giorda, Roberto, Dionne, Ginette, Plourde, Vickie, Vitaro, Frank, Brendgen, Mara, Boivin, Michel, & Marino, Cecilia. (2017). Complex effects of dyslexia risk factors account for ADHD traits: evidence from two independent samples. Journal of Child Psychology and Psychiatry (58)1, 75-82. https://papyrus.bib.umontreal.ca/xmlui/bitstream/handle/1866/20913/Mascheretti_2017_id_5623.pdf?sequence=1

21. Mills, Jeremy R., & Clarke, Monica. (2017). Dyslexia and the need for teacher training: a collaborative three-pronged approach between a university and a community partner. Leadership and Research in Education (4)1, 77-89. https://files.eric.ed.gov/fulltext/EJ1160817.pdf