Dyslexia: What to Know

October 8, 2021

Dyslexia is a widely researched and discussed learning disability. The official definition, written and compiled by Reid Lyon and Sally and Bennett Shaywitz, reads as follows:

“Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge” (Lyon, Shaywitz, & Shaywitz, 2003, p. 2).

To help understand the complexities within this definition, the authors highlighted the following terms from the definition:

Specific Learning Disability (SLD)
This term describes students who struggle to achieve in school despite a normal range of intelligence and access to adequate educational services. A designation of SLD can include difficulty with all parts of language used in school, such as the ability to listen, think, speak, read, write, spell, or to do mathematical calculations (IDEA, 2004).

Neurobiological in Origin
Current research using FMRI shows that dyslexia originates in the brain and that there is ineffective communication between the areas responsible for language processing. This can result in the slow and laborious reading that is often a hallmark symptom of dyslexia (Shaywitz, 2020).

Phonological Component of Language
The ability to understand that individual speech sounds make up words. The capability to discern, segment, and manipulate sounds in words is a foundational reading skill, and students who struggle with this important aspect of language can experience challenges with decoding, fluency, and spelling (Moats, 2008).

Individuals with dyslexia have innate intelligence, but despite capabilities in reasoning and understanding, they can often have unexpected struggles with mastering reading and writing (Lyon et al., 2003, p. 7).

Secondary Consequences
School is a language heavy environment. From an early age, students access information and demonstrate their understanding of content through reading, writing, listening, and speaking. These essential language skills are interconnected and inform, support, and influence one another. Thus, it can be expected that if one area of language is impacted, then other ones will be too (Moats, 2008). For example, if a student is struggling to decode text, it may be assumed that their comprehension will be impacted, and if comprehension is impacted, then it may be assumed that their ability to express their understanding in writing will also be affected.

Understanding this definition helps educators see the layers and complexities involved when a student is diagnosed with dyslexia.


Individuals With Disabilities Education Act, 20 U.S.C. § 1400 (2004).

Lyon, G. R., Shaywitz, S. E., & Shaywitz, B. A. (2003). Defining dyslexia, comorbidity, teachers’ knowledge of language and reading: A definition of dyslexia. Annals of Dyslexia, 53: 1-14.

Moats, L. C., & Dakin, K. E. (2008). Basic Facts About Dyslexia and Other Reading Problems. Baltimore, MD: International Dyslexia Association.

Shaywitz, S. E. (2020). Overcoming dyslexia (2nd edition). New York: Vintage Books. 

Books About Dyslexia

Overcoming Dyslexia by Sally Shaywitz

Basic Facts About Dyslexia and Other Reading Problems by Louisa Moats and Karen Dakin

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