Types of Dyslexia Explained

By Laura Lurns · Reviewed by Philip Weaver · Last reviewed 2026-09-30

Somebody used a word, and now you are here

A report came home with a type name in it. Or a tutor used one. Or a web page listed four types, and your child seemed to fit two, or none. Here is what each name points at.

What the 2025 definition says can vary

The IDA adopted its new definition in October 2025. It was the first change since 2002. It describes trouble with reading words, spelling, or both. That trouble can be in accuracy, speed, or both. It varies "depending on the orthography". That word means the way a language is spelled.

Read closely, the definition gives you four questions. In our view, each answer changes what you would work on.

Reading words, spelling, or both

These are two jobs. The definition says word reading "and/or" spelling. So a child can have trouble with one and not the other. Which one is hard tells you where the practice goes.

Accuracy, speed, or both

Some children get the words right, but slowly and with great effort. Others read fast and get many words wrong. These look very different at the kitchen table. In our view, they need different practice. To us, the child who gets words wrong needs those words taught. For the slow, careful child, we would add lots of reading they can already manage.

How much

The definition puts the trouble "along a continuum of severity". In our view, there is no natural line on it with dyslexia on one side. Catts and colleagues (2026) wrote the paper on the revision. They report a disagreement about where that line belongs. In our view, where the line goes is a choice made against a standard. To us, it is not something found in the child. To us, that is one reason two careful experts can disagree about one child.

Which language

The IDA added the point about spelling systems in 2025. English has kept many spellings that do not match their sounds. Reading a language with more regular spelling is a different task. If your child reads in two languages, tell whoever is helping.

The names you will meet

In our view, these are terms, not separate diagnoses. They come from different places. Here is what each one points at.

Phonological dyslexia

This name points at the sound side of reading. Hearing that cat is three sounds. Keeping them in order. Matching them to letters. In our experience, the term gets used two ways. Some people use it for one pattern. Others use it loosely to mean dyslexia itself.

The 2002 definition already hedged here. It said the trouble typically comes from a weakness in the sound part of language. It did not say it always does. For twenty-three years, people quoted it as if that word were not there. The 2025 definition says it openly. The IDA says trouble with word sounds and word parts is "common but not universal" in dyslexia. With those words, the field is declining to treat the sound account as complete.

Our position, not the IDA's, is that reading draws on more than one system. In our view, a set of questions only about phonics will miss trouble elsewhere.

None of this is a reason to teach less phonics. Sounding out is the only way to handle a word a child has never seen. It does most of the work, most of the time.

Surface dyslexia, dyseidetic, orthographic

These names point at the other job. That is recalling a whole word, rather than working it out.

There are two ways to spell a word, and a skilled speller uses both. One is turning the sounds into letters. The other is recalling the stored spelling of that word.

Words that sound alike show why both are needed. You cannot spell their by sounding it out. It sounds just like there. The letters have to be stored. The same goes for to, too and two. It goes for every odd spelling English has kept. That is a fact about how English is written, not a finding about children.

Niolaki and colleagues (2023) compared 641 UK children at different stages of elementary school. Older children spelled odd words more from stored whole-word forms. Odd words drew on stored forms more than regular words did. Made-up words drew on them less than odd words did. That study measured spelling, not reading. Surface and orthographic are reading terms. In our view, they point at these same two jobs.

Children build stored spellings on top of sounding out, not instead of it.

In our view, this is where the idea of types goes wrong. Both routes are in every speller. This is not two kinds of child. A child can be fine at one route and stuck on the other. Teaching the stored spelling directly is a separate job from teaching the sounds.

Visual dyslexia, and reversed letters

In 2009, the American Academy of Pediatrics and three eye-care bodies stated that vision problems do not cause dyslexia. The American Academy of Ophthalmology was one of the three eye-care bodies. In 2009, pediatric and eye-care bodies said children with dyslexia have no more visual problems than others. They also said reversals are not part of dyslexia's definition. The American Association for Pediatric Ophthalmology and Strabismus advises: "Don't recommend vision therapy for patients with dyslexia."

On their own, reversals neither point to dyslexia nor rule it out. Note them, and watch the reading and the spelling too.

We are not against eye care. The point is narrow. Tracking a line, holding the eyes steady on one point and shifting focus can be practiced. Practice improves them. Keep any such practice alongside reading instruction, not in place of it. Have the eyes checked because eyes should be checked. Do not buy a course of eye exercises as a way to fix reading.

Deep dyslexia, and names from other subjects

To us, deep dyslexia belongs to studies of adults who lost reading after a brain injury. That is not the same as a child learning to read for the first time. In our view, other names spread online without ever having one settled meaning.

Our rule is to keep adult and child research apart. Where they agree, we call that two findings pointing the same way, not one finding. To us, research on adults cannot tell you what such a name means for your child.

So ask whoever used the word two questions. What did you see that made you use it? And what would you change on Monday because of it? Those two questions have answers you can use.

Can a test tell you which type?

Catts and colleagues (2026) write that "no behavioral, genetic, or neurological correlate, beyond difficulties in word-level literacy, shows consistency at the individual level that is necessary to reliably identify dyslexia."

By their account, nothing beyond the reading and spelling trouble reliably identifies dyslexia in one child. No scan or gene test does. What is left to look at is the reading and the spelling themselves. In our view, no test can sort a child into a type either.

Catts and colleagues say the definition's features are "meant to guide professional reasoning rather than prescribe specific assessment thresholds, diagnostic procedures, or instructional methods". They add that the definition "carries no direct legislative or regulatory authority." In our view, it is a description to help people think. To us, it is not a tool for sorting children into groups.

What to ask instead of which type

To us, a type name is worth having only if it changes what somebody does. Some people use types to sort children into kinds of learner. Then they match the teaching to the kind. We do not work that way. The two routes do not support it either, because both are in every speller.

We work from order. Which job of reading is not built yet? Which one do you teach first? The order below is our working model, not a measured finding. Children work on several at once.

• Can your child hear the separate sounds in a spoken word, and put them back together?
• Can they get from letters to sounds reliably, even for a word they have never seen?
• Can they recall the spelling of a word the sounds will not give them?
• Do they read fast enough to leave room for the meaning?

Each answer points to a next step. In our view, that is what a type name was standing in for.