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What Is Dyslexia? Understanding the New 2025 Definition and Why It Matters
- Joanne Kaminski
- 5 days ago
- 6 min read
Updated: 1 day ago
What the Old Definition of Dyslexia Said (2002)
For over two decades, the definition of dyslexia was focused almost entirely on phonological processing difficulties. According to the 2002 IDA definition:
“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.”
It also emphasized that these difficulties were often "unexpected" given the child's other cognitive abilities and adequate classroom instruction.
Many states including New Jersey, Ohio, and Utah adopted this language into their education codes.
What the New Definition of Dyslexia Says (2025 Draft)
The 2025 revision reflects a more current, inclusive understanding:
"Dyslexia is a specific learning disability characterized by difficulties in word reading—affecting accuracy, speed, or both—and/or spelling, that can vary depending on the written language system. These difficulties reflect performance at the low end of a continuum of literacy skill and occur despite evidence-aligned instruction that is effective for the individual’s peers. The cause and development of dyslexia involve the interplay of multiple biological and environmental influences. Phonological and/or morphological difficulties are common but not always present. Among the secondary consequences are limitations in language development and academic progress as well as challenges to psychological well-being and vocational opportunities. Although identification and targeted instruction are important at any age, language and literacy support before and during the early years of education can be particularly effective."
It recognizes that dyslexia is shaped by multiple biological and environmental influences.
Phonological and/or morphological difficulties are common, but not always present.
Secondary effects may include challenges in academic progress, language development, psychological well-being, and vocational success.
Old vs. New Definition (Comparison Chart)
Aspect | 2002 Definition | 2025 Draft |
Cause | Neurobiological only | Biological + Environmental |
Core Difficulty | Word recognition, spelling, decoding | Word reading (accuracy, speed), spelling |
Language Variability | Not specified | Varies by writing system |
Instruction Context | Difficulties are "unexpected" | Difficulties occur despite evidence-aligned instruction |
Common Deficits | Phonological | Phonological and/or morphological |
Viewpoint | Deficit compared to abilities | Low end of a literacy continuum |
Secondary Consequences | Comprehension, vocabulary | Academic, emotional, vocational impact |
Support Timing | Not emphasized | Early support is critical |
My Perspective as a Reading Specialist and Dyslexia Therapist
When I read the revised definition, I felt deeply affirmed. For years, I worked with students who didn’t neatly fit the older, phonology-focused model—but clearly struggled with dyslexia.
One student in particular stands out: Kevin.
When the Old Definition Didn't Fit: Kevin’s Story
Kevin was a bright third grader reading at a first-grade level. His comprehension was exceptional, he could explain stories with clarity and depth, but his reading was painfully slow and full of mistakes. I assessed his phonemic awareness expecting to see red flags, but they weren’t there. Still, I had a strong suspicion that dyslexia was the issue.
After I shared my observations with his mother, she pursued a formal evaluation. Kevin was diagnosed with dyslexia. He wasn’t an outlier, but rather he was one of many students I’d seen whose challenges were missed by the old definition, but made complete sense in light of the new one.
What are the Brain Differences Between Typical Readers and Readers with Dyslexia?
Research using brain imaging (like fMRI) shows that children with dyslexia do process reading differently:
Typical readers: When they read, the left side of the brain “lights up” in three key areas—responsible for recognizing written words, connecting them to sounds, and processing meaning. These pathways become fast and automatic with practice.
Readers with dyslexia: Those left-side pathways don’t activate in the same way. Instead, they may rely more on the right hemisphere or frontal areas of the brain, which makes reading slower and less efficient.
What is Dyslexia? How do typical readers and readers with dyslexia differ?
That’s why even bright kids with dyslexia can feel like reading is exhausting—they’re using “detours” in the brain instead of the quick, well-paved routes that typical readers build.
Why Early Identification Is a Game-Changer
One of the most important additions to the 2025 definition is its emphasis on early support. We can now detect risk factors for dyslexia in kindergarten—and when we intervene early, we can dramatically improve outcomes.
I worked with a pair of kindergarten twins who showed early signs of phonemic awareness struggles. By starting structured support immediately, they remained on grade level with their peers and avoided the frustration, low self-esteem, and academic gaps that often emerge when dyslexia is caught too late.
What Parents Should Know
Dyslexia is not always about phonological deficits
It’s influenced by both nature (brain differences) and nurture (environment and teaching)
It exists on a continuum of reading ability
Early signs can appear in kindergarten
Early, targeted instruction leads to dramatically better outcomes
If your child is struggling with reading—whether they’re in kindergarten or middle school—it’s never too early (or too late) to get help. However, starting earlier means greater success earlier for all academic areas.
What Should Instruction Include?
If you suspect your child may have dyslexia—or if they’ve already been identified—it’s critical to ensure their instruction includes the following components. These steps aren’t just helpful; they’re essential for building strong reading foundations.
1. Phonological Awareness (Listening to Sounds)
In the early grades (kindergarten and first), instruction should start with strong phonological awareness—the ability to hear and manipulate the sounds in words.
This is a listening skill but has a direct connection to writing (encoding).
When a child writes, they use phonological skills to think through the sounds they hear. Helping them break words into sounds and write those sounds down builds a bridge between listening and spelling.
2. Letter Formation and Visual Discrimination
Early readers also need help distinguishing and forming similar letters, like b, d, p, and q. This isn’t just handwriting—it’s cognitive clarity.
Imagine having to pause and decide, every time you see a word, whether it’s a “b” or a “d.” It adds enormous strain to the reading process. Clear, repeated instruction in letter formation builds fluency and confidence.
3. Systematic Phonics & Vowel Pattern Instruction
Once a child understands basic sounds, they need to learn how vowels work—one of English’s trickiest areas.
Teach the six basic syllable types (CVC, CVCE, vowel teams, etc.)
Help them understand that vowels change sounds depending on patterns and context (e.g., a in “apple,” “lake,” and “walk” all sound different).
To learn more about the 6 basic syllable types read this blog post Phonics Rules: An incredibly easy method that works for all
4. Appropriate Reading Material: Decodable and Leveled Texts
Students with dyslexia benefit from decodable readers—books that use only phonics rules they’ve been taught.
As they gain skills, use leveled books that match their decoding ability
Avoid books that are too advanced, as this can cause frustration and fatigue
5. Sight Word Instruction Using an Orthographic Approach
Sight words should be taught explicitly—but with multisensory support.
For example, a child might hear “said” and write S-E-D based on the sounds. A teacher can then guide them: “Great! The /s/ and /d/ are correct. But here, the ‘ai’ makes the /e/ sound. So it’s spelled S-A-I-D.”
To build retention:
Skywrite with a straight arm and large motions
Finger trace on gel boards or sand trays
Tap sounds out on arms or fingers
Use color-change tools or high-contrast writing materials
Repetition is key. Unlike typical readers, dyslexic students need many exposures to a word before it becomes automatic.
6. Fluency: Reading with Flow and Expression
Once phonics is in place, students should practice reading aloud with attention to:
Punctuation cues (pausing at commas, changing tone for questions)
Prosody—reading with rhythm and expression
Repetition of familiar texts to build speed
Scarborough’s Rope is a great visual for how all the aspects of reading come together even if a child has dyslexia.
Each reading skill is a strand. As strands strengthen and twist together, reading becomes more fluent and automatic. But if one strand is weak or missing, the whole rope weakens.
7. Comprehension: The Ultimate Goal
Reading is more than decoding—it’s about understanding. Instruction should always include comprehension questions that:
Check basic understanding
Encourage higher-level thinking (e.g., inference, prediction, cause/effect)
Every child deserves to not only read the words—but to understand and enjoy what they read.
About the Author
Joanne Kaminski is a certified reading specialist and trained in the Orton–Gillingham approach, as well as a member of the International Dyslexia Association. She's currently based in Sussex, Wisconsin. She serves students locally and online throughout the U.S., Canada, and beyond. She specializes in early identification and structured literacy interventions for students with dyslexia and related reading difficulties. Connect with Joanne on LinkedIn or by setting up a free reading assessment to see what grade level your child is reading at.
If you're wondering whether your child’s reading challenges might be dyslexia—or if you’re just not sure what next steps to take—Joanne offers free consultations for parents.
Let’s talk about how we can support your child’s reading success from the very start.
