Dyslexia

What it is

A specific learning difference affecting accurate and fluent word reading, decoding, and spelling. It is not related to intelligence or effort.

Common experiences

Reading can be slow and tiring. Many dyslexic people describe strengths in big-picture thinking, storytelling, and creative problem-solving.

What helps

Structured literacy instruction, audiobooks, text-to-speech, extra time, and readable fonts with generous spacing.

Across life

Early signs include trouble learning letter sounds, rhyming, and sounding out words. Later signs include slow, effortful reading, spelling errors, and avoiding reading aloud. Adults often still read slowly while having strong spoken vocabulary and reasoning.

Evaluation and treatment

An educational or clinical psychologist or qualified specialist assesses reading, decoding, spelling, and phonological skills. Structured literacy teaching helps at any age, and accommodations include extra time, audiobooks, and text-to-speech.

Myth vs fact

Myth: dyslexia means seeing letters backwards. Fact: it is mainly a difficulty linking sounds to letters. Letter reversals are common in all beginning readers.

Full chapter

Definitions and criteria

Dyslexia is a specific learning difficulty that mainly affects accurate and fluent word reading and spelling (Rose, 2009; Snowling et al., 2020). The DSM-5-TR places it under specific learning disorder with impairment in reading, covering word reading accuracy, reading rate or fluency, and reading comprehension, and notes dyslexia as an alternative term for a pattern of difficulties with accurate or fluent word recognition, poor decoding, and poor spelling. The ICD-11 uses the term developmental learning disorder with impairment in reading. The difficulties must be well below what is expected for age, persist despite teaching, and not be better explained by intellectual disability, vision or hearing problems, or lack of instruction. The International Dyslexia Association definition (Lyon et al., 2003) also describes dyslexia as neurobiological in origin and unexpected given a person's other abilities and the quality of their teaching.

A continuum, not a switch

Reading ability is spread along a continuum, and researchers have long argued that dyslexia sits at the lower end rather than being a separate category (Shaywitz et al., 1992). Snowling, Hulme, and Nation (2020) therefore describe dyslexia as a dimensional difficulty in which persistent problems despite good teaching are central to identification. This is why estimates of how common dyslexia is vary with the cutoffs used, and why people just above a cutoff can still need support (Peterson & Pennington, 2012).

Causes and the brain

Dyslexia runs in families, and genetic factors play a substantial role (Peterson & Pennington, 2012). The most widely supported explanation involves differences in processing the sound structure of language, known as phonological processing, although current models describe several interacting risk factors rather than a single cause (Pennington, 2006). Brain imaging studies find differences in activity in left-hemisphere regions that support reading (Richlan et al., 2009). Dyslexia is not caused by poor vision, laziness, or low intelligence (Handler & Fierson, 2011; Lyon et al., 2003).

Dyslexia across languages

Learning to read is slower in English than in languages with more regular spelling (Seymour et al., 2003), so dyslexia can look different across languages and writing systems. Multilingual learners need assessments that consider all of their languages rather than only the language of schooling.

Early signs

Children at family risk often show differences in early spoken language and sound awareness before they begin to read (Snowling & Melby-Lervag, 2016). Signs before school include late talking, trouble with rhymes, and difficulty learning letter names and sounds. At school, signs include slow, effortful reading, guessing at words from pictures or first letters, trouble sounding out unfamiliar words, and inconsistent spelling. Early difficulty is not a reason to wait: systematic phonics teaching works best when it starts early (National Reading Panel, 2000), and support still helps at any age.

Dyslexia in teens and adults

Students with dyslexia who reach higher education still show persistent problems with reading speed, spelling, and phonological skills (Callens et al., 2012). Adults often describe taking much longer to read, avoiding reading aloud, relying on context and memory, re-reading to catch the meaning, and finding spelling and written forms stressful, while their spoken vocabulary and reasoning may be strong. Many adults are identified only after a child is assessed or a new job or course raises the demands.

Girls, boys, and who gets identified

When children are screened systematically, dyslexia occurs in girls and boys at similar rates, but schools refer boys more often, which suggests referral bias (Shaywitz et al., 1990). Quiet children who compensate well, whatever their gender, can be missed.

Co-occurring differences

Dyslexia often occurs with ADHD (Willcutt & Pennington, 2000), and also with developmental language disorder, dyscalculia, dysgraphia, and developmental coordination disorder. Pennington (2006) proposed multiple-deficit models to explain why neurodevelopmental conditions overlap so often. A thorough assessment looks at the whole profile, including attention, language, motor skills, and mental health.

Emotions, confidence, and mental health

Struggling with reading in a world built on text can erode confidence. Literacy difficulties are linked to higher rates of emotional and behavioral difficulties (Carroll et al., 2005), and reviews describe anxiety, low self-esteem, and school avoidance among people with dyslexia (Livingston et al., 2018). Early identification, effective teaching, and an understanding school or workplace protect wellbeing, and people often describe relief on learning the reason for their difficulties. If you are struggling or having thoughts of suicide, please see the Crisis help page.

Getting assessed

An assessment looks at word reading, reading of made-up words, reading fluency, spelling, phonological awareness, rapid naming, and oral language, along with developmental, educational, and family history, and rules out vision, hearing, and other contributors. The Rose Review in England (2009) emphasized that how a child responds to well-founded teaching is central to judging the severity and persistence of difficulties. Assessment can be done by educational or clinical psychologists or qualified specialist teachers, and rules about who can diagnose vary by country. Vision therapy and colored lenses are not recognized treatments for dyslexia (Handler & Fierson, 2011).

Teaching that works

A major review of research found that systematic phonics instruction, together with teaching of phonological awareness, helps children learn to read (National Reading Panel, 2000). A meta-analysis of randomized trials found that phonics instruction was the only approach with a statistically confirmed effect on reading and spelling for children and adolescents with reading disabilities (Galuschka et al., 2014). Structured literacy, which teaches the sounds and structure of language explicitly, systematically, and cumulatively, is the approach the International Dyslexia Association recommends. A review of Orton-Gillingham programs concluded that evidence for them as a distinct brand is limited because few high-quality studies exist, although they share the explicit, systematic teaching that research supports (Stevens et al., 2021). Instruction should be intensive and delivered by trained teachers.

Accommodations and technology

Audiobooks, text-to-speech, speech-to-text, spell-checkers, extra time, clear layouts, and alternatives to reading aloud remove barriers while skills are built. A meta-analysis found that text-to-speech and read-aloud tools improved reading comprehension for students with reading disabilities (Wood et al., 2018). Accommodations complement instruction; they do not replace it.

Fonts, spacing, and layout

Extra-large letter spacing improved reading in children with dyslexia in one study (Zorzi et al., 2012), while a study of the OpenDyslexic font found no reading benefit compared with common fonts (Wery & Diliberto, 2017). The British Dyslexia Association style guide (2018) recommends plain sans-serif fonts, generous spacing, left-aligned text, short lines, and clear headings. That is why this site offers adjustable text size and spacing and lets you choose the font that feels best.

School, work, and rights

In the United States, dyslexia can qualify a student for an individualized education program under the IDEA as a specific learning disability, and the U.S. Department of Education has confirmed that the term can be used in evaluations and plans (U.S. Department of Education, 2015); Section 504 and the ADA provide accommodations at school and work. In Canada, Ontario's Right to Read inquiry (Ontario Human Rights Commission, 2022) concluded that many students with reading disabilities were not identified early or taught with evidence-based methods, and recommended universal screening and systematic, evidence-based instruction; provincial human rights codes require accommodation to the point of undue hardship. At work, useful adjustments include text-to-speech, speech recognition, extra time, written and audio instructions, and templates. Laws and eligibility vary, so confirm locally, and see the Resources page.

Strengths and identity

Many dyslexic people describe strengths such as creative problem solving, storytelling, spatial thinking, and persistence built through years of working around obstacles. Research on whether such strengths are more common in dyslexia than in other people is mixed, so strengths are best seen as individual, not universal, and they never replace the need for effective teaching and accommodations. Dyslexia is unrelated to intelligence (Lyon et al., 2003), and dyslexic people succeed in every field.

For families, teachers, and colleagues

Believe that the struggle is real and not about effort. Praise effort and ideas, avoid asking someone to read aloud on the spot, offer audio and written options, give extra time without making it conspicuous, and mark ideas separately from spelling. Parents can read aloud together, keep books and audiobooks around, and seek an evaluation and structured literacy teaching early rather than waiting. The Resources page lists dyslexia and learning difference organizations.

Sources

1. Rose, J. (2009). Identifying and teaching children and young people with dyslexia and literacy difficulties: An independent report. Department for Children, Schools and Families.
2. Snowling, M. J., Hulme, C., & Nation, K. (2020). Defining and understanding dyslexia: past, present and future. Oxford Review of Education, 46(4), 501-513.
3. American Psychiatric Association. (2022). Diagnostic and Statistical Manual of Mental Disorders (5th ed., text rev.).
4. World Health Organization. International Classification of Diseases, 11th Revision (ICD-11), section on developmental learning disorder with impairment in reading.
5. Lyon, G. R., Shaywitz, S. E., & Shaywitz, B. A. (2003). A definition of dyslexia. Annals of Dyslexia, 53, 1-14.
6. Shaywitz, S. E., Escobar, M. D., Shaywitz, B. A., Fletcher, J. M., & Makuch, R. (1992). Evidence that dyslexia may represent the lower tail of a normal distribution of reading ability. New England Journal of Medicine, 326(3), 145-150.
7. Peterson, R. L., & Pennington, B. F. (2012). Developmental dyslexia. The Lancet, 379(9830), 1997-2007.
8. Pennington, B. F. (2006). From single to multiple deficit models of developmental disorders. Cognition, 101(2), 385-413.
9. Richlan, F., Kronbichler, M., & Wimmer, H. (2009). Functional abnormalities in the dyslexic brain: A quantitative meta-analysis of neuroimaging studies. Human Brain Mapping, 30(10), 3299-3308.
10. Handler, S. M., Fierson, W. M., et al. (2011). Learning disabilities, dyslexia, and vision. Pediatrics, 127(3), e818-e856.
11. Seymour, P. H. K., Aro, M., & Erskine, J. M. (2003). Foundation literacy acquisition in European orthographies. British Journal of Psychology, 94(2), 143-174.
12. Snowling, M. J., & Melby-Lervag, M. (2016). Oral language deficits in familial dyslexia: A meta-analysis and review. Psychological Bulletin, 142(5), 498-545.
13. Callens, M., Tops, W., & Brysbaert, M. (2012). Cognitive profile of students who enter higher education with an indication of dyslexia. PLoS ONE, 7(6), e38081.
14. Shaywitz, S. E., Shaywitz, B. A., Fletcher, J. M., & Escobar, M. D. (1990). Prevalence of reading disability in boys and girls: Results of the Connecticut Longitudinal Study. JAMA, 264(8), 998-1002.
15. Willcutt, E. G., & Pennington, B. F. (2000). Comorbidity of reading disability and attention-deficit/hyperactivity disorder: Differences by gender and subtype. Journal of Learning Disabilities, 33(2), 179-191.
16. Carroll, J. M., Maughan, B., Goodman, R., & Meltzer, H. (2005). Literacy difficulties and psychiatric disorders: Evidence for comorbidity. Journal of Child Psychology and Psychiatry, 46(5), 524-532.
17. Livingston, E. M., Siegel, L. S., & Ribary, U. (2018). Developmental dyslexia: Emotional impact and consequences. Australian Journal of Learning Difficulties, 23(2), 107-135.
18. National Institute of Child Health and Human Development. (2000). Report of the National Reading Panel: Teaching children to read (NIH Publication No. 00-4769).
19. Galuschka, K., Ise, E., Krick, K., & Schulte-Korne, G. (2014). Effectiveness of treatment approaches for children and adolescents with reading disabilities: A meta-analysis of randomized controlled trials. PLoS ONE, 9(2), e89900.
20. Stevens, E. A., Austin, C., Moore, C., Scammacca, N., Boucher, A. N., & Vaughn, S. (2021). Current state of the evidence: Examining the effects of Orton-Gillingham reading interventions for students with or at risk for word-level reading disabilities. Exceptional Children, 87(4), 397-417.
21. Wood, S. G., Moxley, J. H., Tighe, E. L., & Wagner, R. K. (2018). Does use of text-to-speech and related read-aloud tools improve reading comprehension for students with reading disabilities? A meta-analysis. Journal of Learning Disabilities, 51(1), 73-84.
22. Zorzi, M., et al. (2012). Extra-large letter spacing improves reading in dyslexia. Proceedings of the National Academy of Sciences, 109(28), 11455-11459.
23. Wery, J. J., & Diliberto, J. A. (2017). The effect of a specialized dyslexia font, OpenDyslexic, on reading rate and accuracy. Annals of Dyslexia, 67(2), 114-127.
24. British Dyslexia Association. (2018). Dyslexia style guide.
25. U.S. Department of Education, Office of Special Education and Rehabilitative Services. (2015). Dear Colleague Letter: Dyslexia guidance (October 23, 2015).
26. Ontario Human Rights Commission. (2022). Right to Read: Public inquiry into human rights issues affecting students with reading disabilities.

Citations are listed so you can verify claims and read further. Guidance is revised over time, so check for newer editions.