My six-year-old still writes b instead of d. Is that dyslexia?

On its own, no. Reversing letters is common in children who are just learning to read and write, including children who never have any reading difficulty at all. It was once treated as a hallmark of dyslexia and the evidence for that turned out to be mixed. What matters is whether reading itself is moving forward.

Should I speak to a doctor or to the school?

The school, and specifically the class teacher, first. They see your child reading every week alongside a whole class, which is a comparison you cannot make at home, and in most systems the route to any formal assessment runs through the school rather than through a clinic.

How do I know whether my child is just a late reader?

Often you cannot tell yet, and nobody honest will tell you they can from a list. What you can do is describe specifically what you see to the teacher and ask whether it matches what they see. That single conversation sorts out most cases faster than any checklist.

Is it too early to raise it?

Almost certainly not. The evidence on reading instruction consistently shows a larger benefit when help starts early than when it starts later, and asking a question costs nothing and closes nothing off.

Does Plimmery tell me whether my child has dyslexia?

No. Plimmery does not screen for dyslexia and produces no result that means anything clinically. It can show you what your child is working on and where they keep getting stuck, which is useful material to bring to a teacher, and that is all it is.

Should I tell my child I think they might be dyslexic?

No. That is not a label for a parent to apply at home, and a child who hears it will carry it. Describe what you notice to the teacher instead, and let the people who can actually assess it do the assessing.

plimmery

Indicators, not a diagnosis

When to be concerned about your child's reading

Most of the time the honest answer is that it is early yet. This page is about telling that apart from the case where someone should take a closer look.

Three things before you read on

Nothing on this page is a diagnosis. These are indicators: things that, across large groups of children, tend to travel with later reading difficulty. They describe patterns in thousands of children. They cannot tell you anything certain about yours.
Start with the class teacher, not a doctor. A teacher watches your child read every week next to a whole class of children the same age. That comparison is the single most useful piece of information available, and you cannot make it at your kitchen table.
The phrase is “worth a conversation”. Not warning sign, not red flag. Raising something early costs nothing and rules nothing out.

Things that worry parents, and should not

These come first because, for most people reading this page, this is the section that is true.

Writing b for d, and letters facing the wrong way

Reversing letters is ordinary in children who are just learning to read and write. It was once treated as a hallmark of dyslexia, and the evidence for that turned out to be mixed: reversals show up plenty in beginning readers who go on to have no difficulty at all [1]. In the same study, the early brain response to a backwards letter was still immature even in older children who had long stopped reversing letters on paper. The machinery is simply still being built. While reading itself is moving forward, notice it and move on.

Progress that stalls, then jumps

Reading does not arrive on a schedule. Weeks of apparently nothing followed by a sudden step is the normal shape of it, not a problem. What matters is the direction over a term, not the slope over a fortnight.

Slower than a sibling, or than the child next door

The strongest early predictor anyone has found is how many letters a child knows before school, and it correlates with later reading at about .50 [2]. That sounds decisive until you translate it: it accounts for roughly a quarter of the differences between children. The other three quarters is something else. Sibling comparisons are worth even less than that.

Not reading at four

Four-year-olds who are not reading are four-year-olds. Formal reading instruction starts at different ages in different countries, by years, and children in the later-starting systems catch up fine.

Worth a conversation, by age

Read the ages as “after a year or so of being taught”, not as birthdays. School systems begin formal reading instruction years apart, so a six-year-old in one country has had far more teaching than a six-year-old in another. None of these is a test to score your child against. Any one of them is a reasonable thing to mention to a teacher.

Around 5

After a year or so of being taught letters

Does not know the names or the sounds of most letters
Cannot hear that two words rhyme, or come up with a rhyme
Cannot tell you the first sound in a spoken word
Cannot write their own name

Around 6

After being shown, repeatedly, how to sound a word out

Cannot blend a simple three-sound word such as cat or pin
Still does not link letters to sounds reliably from one day to the next
Has started avoiding books, or gets upset when reading comes up

Around 7

Once simple stories are the everyday reading material

Reading is still slow and word by word, with little sense of the sentence
Words with two consonants together, stop or hand or clap, come apart
Spelling attempts look nothing like the sounds in the word

Around 8 to 9

When reading turns into a tool for learning other things

Reads the words on the page accurately and cannot say what happened
Longer words with several syllables stop them dead
Reading is still exhausting rather than something they forget they are doing

Why those particular things

The list for the youngest band is not a hunch. A national panel pooled decades of studies to find out which early skills actually predict how well a child reads later, and six of them held up even after things like family background and general ability were accounted for [2].

Knowing letters came out strongest, correlating .50 with later reading across 52 studies and 7,570 children. Sound awareness, meaning hearing the separate sounds inside a spoken word, came in at .40 across 69 studies and 8,443 children. Being able to write letters or one's own name reached .49. And rapid naming, being able to reel off a row of letters or digits quickly, reached .40 [2]. That last one sounds like a party trick and is not: speed of retrieval turns out to matter.

Notice how far those numbers are from certainty. A correlation of .50 is about as good as early prediction of reading gets, and it still leaves most of the variation between children unexplained. That is the honest reason this page keeps saying “indicator” instead of “sign”.

If reading was hard for you too

Mention it. Reading difficulty runs in families, and it is useful information rather than a confession. A review of 95 publications covering 21 independent samples found that children with a parent or sibling with dyslexia tend to show delayed language as infants and toddlers, and difficulty in the preschool years with sound awareness, letter knowledge and rapid naming [3]. The same review found something worth holding onto: children in those families who went on to read normally still scored below children with no family history. A family history shifts the odds. It does not decide anything.

Why “wait and see” is the weaker option

The largest review of reading instruction found the benefit of systematic teaching noticeably larger when it began early, an effect size of 0.55, than when it began later, 0.27 [4]. Effect size is researchers' shorthand for how big a difference something made, and the gap between those two numbers is the cost of waiting.

There is a second cost that no meta-analysis measures. A child who spends two years quietly deciding they are the one who is bad at reading has to be talked back out of that before any teaching can land. Raising a question in the autumn term is cheap. Raising it three years later is not.

What to actually do

Write down what you see, with examples, for a week. “He looks at the picture and guesses.” “She knows the sound on Monday and not on Thursday.” Specifics land. “I'm worried” does not.
Ask the class teacher for ten minutes. Ask what they see, whether it matches your list, and what the school already does to check.
Ask about the checks the school already runs. Most systems have some kind of routine early reading check. Find out what your child's showed.
Keep reading aloud together, every day, long past the point where they can read alone. Nothing on this list matters more and nothing else is as easy.
If the teacher shares your concern, ask what the route to a proper assessment looks like. In most systems that route starts at the school.
Do not put a label on your child at home. Describe what you notice to the adults who can actually assess it, and let them do the assessing.

What this page cannot tell you

Every figure here is a group-level finding. Correlations between .40 and .50 describe patterns across thousands of children [2]. They do not predict one child, and anyone who tells you otherwise is selling something.
The age bands are approximate and are tied to how much teaching a child has had, not to birthdays.
We deliberately publish no reading-speed cutoffs. Those norms exist and teachers use them properly, but they are tied to specific tests, languages and school systems. A bare number lifted out of that context is far more likely to frighten you than to inform you.
Plimmery does not screen for dyslexia and gives no result that means anything clinically. It can show you what your child is working on and where they keep getting stuck, which is useful material for that ten-minute conversation. It is a supplement to teaching, never a replacement for it, and never a replacement for you.

Questions parents ask

My six-year-old still writes b instead of d. Is that dyslexia?: On its own, no. Reversing letters is common in children who are just learning to read and write, including children who never have any reading difficulty at all. It was once treated as a hallmark of dyslexia and the evidence for that turned out to be mixed. What matters is whether reading itself is moving forward.[1]
Should I speak to a doctor or to the school?: The school, and specifically the class teacher, first. They see your child reading every week alongside a whole class, which is a comparison you cannot make at home, and in most systems the route to any formal assessment runs through the school rather than through a clinic.
How do I know whether my child is just a late reader?: Often you cannot tell yet, and nobody honest will tell you they can from a list. What you can do is describe specifically what you see to the teacher and ask whether it matches what they see. That single conversation sorts out most cases faster than any checklist.
Is it too early to raise it?: Almost certainly not. The evidence on reading instruction consistently shows a larger benefit when help starts early than when it starts later, and asking a question costs nothing and closes nothing off.[4]
Does Plimmery tell me whether my child has dyslexia?: No. Plimmery does not screen for dyslexia and produces no result that means anything clinically. It can show you what your child is working on and where they keep getting stuck, which is useful material to bring to a teacher, and that is all it is.
Should I tell my child I think they might be dyslexic?: No. That is not a label for a parent to apply at home, and a child who hears it will carry it. Describe what you notice to the teacher instead, and let the people who can actually assess it do the assessing.

References

Every source below was opened and read before it was cited. Where a figure was not visible in the source we could reach, we left it off the page rather than repeat it secondhand.

[1] Blackburne, L. K., Eddy, M. D., Kalra, P., Yee, D., Sinha, P., and Gabrieli, J. D. E. (2014). Neural correlates of letter reversal in children and adults. PLOS ONE, 9(5), e98386.
doi.org/10.1371/journal.pone.0098386
What we confirmed: Abstract and introduction read in full. States that letter reversal is common in beginning readers, that it was once thought a hallmark of dyslexia but the evidence for a selective tendency in dyslexia is mixed, and that reversals commonly occur in beginning readers without dyslexia. The brain data (children aged 5 to 12) show that the early stages of visual processing still fail to separate typical from reversed letters even in older children who no longer reverse letters in their writing. The paper does not name an exact age at which reversals resolve, so this page does not quote one.
[2] Shanahan, T., and Lonigan, C. J. (2010). The National Early Literacy Panel: a summary of the process and the report. Educational Researcher, 39(4), 279 to 285.
doi.org/10.3102/0013189X10369172
What we confirmed: Full article read. Six early skills held moderate to large predictive relations with later literacy and kept their predictive power after variables such as IQ and family background were accounted for: alphabet knowledge (average correlation .50 with later decoding, 52 studies, 7,570 children), sound awareness (.40, 69 studies, 8,443 children), rapid naming of letters or digits (.40, 12 studies, 2,081 children), rapid naming of objects or colors (.32, 16 studies, 3,100 children), writing letters or one's own name (.49, 10 studies, 1,650 children), and phonological memory (.26 with decoding, .39 with reading comprehension).
[3] Snowling, M. J., and Melby-Lervag, M. (2016). Oral language deficits in familial dyslexia: a meta-analysis and review. Psychological Bulletin, 142(5), 498 to 545.
doi.org/10.1037/bul0000037
What we confirmed: Abstract read in full. Reviews 95 publications based on 21 independent samples of children at family risk of reading disorders. Reports delayed language development as infants and toddlers, preschool difficulty with phonological processes, letter knowledge and rapid naming, and that children at family risk who go on to read normally still do less well than controls.
[4] Ehri, L. C., Nunes, S. R., Stahl, S. A., and Willows, D. M. (2001). Systematic phonics instruction helps students learn to read: evidence from the National Reading Panel's meta-analysis. Review of Educational Research, 71(3), 393 to 447.
doi.org/10.3102/00346543071003393
What we confirmed: Abstract read in full. 66 treatment-control comparisons from 38 experiments. Overall effect d = 0.41; d = 0.55 when instruction began early and d = 0.27 when it began after first grade. Also reports that phonics helped younger students at risk of reading disability and older students with reading disability.