Why The New Definition of Dyslexia Is Important

The International Dyslexia Association (IDA) recently published a new definition of dyslexia, developed through a rigorous and collaborative process to reflect the latest research and the lived experiences of individuals with dyslexia. Members of the Strategies for Learning team, including our Certified Academic Language Therapists, also participated in this important effort.

The New IDA’s Definition of Dyslexia (2025)

“Dyslexia is a specific learning disability characterized by difficulties in word reading and/or spelling that involve accuracy, speed, or both and vary depending on the orthography. These difficulties occur along a continuum of severity and persist even with instruction that is effective for the individual’s peers. The causes of dyslexia are complex and involve combinations of genetic, neurobiological, and environmental influences that interact throughout development. Underlying difficulties with phonological and morphological processing are common but not universal, and early oral language weaknesses often foreshadow literacy challenges. Secondary consequences include reading comprehension problems and reduced reading and writing experience that can impede growth in language, knowledge, written expression, and overall academic achievement. Psychological well-being and employment opportunities also may be affected. Although identification and targeted instruction are important at any age, language and literacy support before and during the early years of education is particularly effective.”

The Old IDA’s Definition of Dyslexia (2002)

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 the growth of vocabulary and background knowledge.”

Why it Matters

A universally accepted definition of dyslexia is crucial—it shapes how schools determine eligibility for services and guides how teachers provide literacy instruction. The new definition better captures the wide range of ways dyslexia can present in students. This updated definition also highlights how environmental factors, such as early reading instruction, can influence how dyslexia manifests. The new IDA definition emphasizes early “identification and targeted intervention”, allowing parents and educators to act proactively—before students begin to fall behind. We’ll dive a little deeper into these two factors.

Early identification

An evaluation can be pursued through the school or privately, each with its own advantages and considerations. One valuable option for early identification is a literacy assessment, such as the Tests of Dyslexia (TOD), now offered by Strategies for Learning. The TOD is specifically designed to detect dyslexia-related patterns by assessing phonological processing, rapid naming, word reading, spelling, and related cognitive-linguistic skills. Because it focuses on these key markers, the TOD can usually be completed in just one or two sessions, making it a practical and accessible choice for families seeking clarity about their child’s reading and writing challenges. The results provide a formal identification of dyslexia risk, which can help guide educational therapy, tutoring, or school-based interventions.

Targted Intervention

Research from the Science of Reading has deepened our understanding of how the brain learns to read—what skills are involved, how they interact, and which instructional methods are most effective. From this extensive body of evidence, we know that Structured Literacy is the most effective approach to teaching foundational reading skills for all students—and absolutely essential for those with dyslexia or other reading difficulties. It is characterized by instruction that is explicit, systematic, cumulative, and diagnostic. It emphasizes direct teaching of key components of language, including phonology, sound-symbol relationships, syllable patterns, morphology, syntax, and semantics.

In recent years, some schools have begun shifting from Balanced Literacy or Whole Language approaches toward more structured, evidence-based reading instruction—a promising step forward, though there is still important work to be done to ensure all students receive the literacy instruction they need to be strong readers.

In Conclusion, the new definition—and the tools we now have to support it—represent an exciting step forward in ensuring that students with dyslexia receive the support they need to thrive.