People With Dyslexia and Reading Differences
Reading differences are common enough that designing for them is designing for a large share of your audience.
Justified text, dense paragraphs, and all caps are decisions — and they cost you readers.
Dense justified paragraphs create uneven word spacing that the eye has to work around. Long lines make it hard to find the start of the next one. All caps removes word shape. Text over a busy image removes the contrast the reader was relying on. None of these produce an error, so nobody reports them — the page just takes three times as long to read, and most people stop.
Scale: Prevalence estimates for dyslexia vary widely, commonly cited between 5% and 20% of the population depending on definition and measurement. (Source: NIH / International Dyslexia Association ranges. Survey-based disability figures undercount — treat this as a floor.)
What they're using
- Text-to-speech and read-aloud tools
- Reader modes and custom stylesheets
- Fonts and spacing adjustments made at the OS or browser level
- Often nothing but a preference for well-set text
5 barriers we find most often, and the criteria behind them.
Typography that fights the reader
Justified text, very long line lengths, tight line height, and all-caps body text all measurably slow reading. None are WCAG Level AA failures by themselves, which is why they survive so long.
Success criteria: 1.4.12 Text Spacing AA
Text that cannot be restyled
If a user increases line height or letter spacing and the layout clips, the accommodation is unavailable.
Success criteria: 1.4.12 Text Spacing AA
Unstructured walls of content
No headings, no lists, no summary. Structure is what lets a struggling reader find the part they need instead of reading all of it.
Success criteria: 1.3.1 Info and Relationships A · 2.4.6 Headings and Labels AA
Jargon, idiom, and unexpanded abbreviations
Plain language is a Level AAA criterion, so it is not required — but it is the single highest-impact editorial change most organizations can make.
Success criteria: 3.1.2 Language of Parts AA
Text baked into images
Cannot be read aloud, cannot be restyled, cannot be searched.
Success criteria: 1.4.5 Images of Text AA
The changes that actually remove the barrier.
Set type for reading
Left-aligned rather than justified, around 60 to 80 characters per line, generous line height, sentence case.
Structure everything
Headings that describe, short paragraphs, lists where a list is what you mean, and a summary at the top of anything long.
Write plainly
Short sentences, common words, expanded abbreviations on first use. This is also how you win featured snippets.
Make sure read-aloud tools work
Real text, correct language attribute, and a heading structure that lets someone skip.
Three tests you can run before you call anyone.
- Run your key page through a readability measure and read the result honestly.
- Apply text-spacing overrides and look for clipping.
- Have the browser read the page aloud and listen for where it goes wrong.
If any of those go badly, you have your answer and you did not need a vendor to get it. What a vendor is for is the part after: knowing which of the 55 criteria that maps to, how deep it goes, and what it costs to fix properly rather than patch.
Run the Free CheckerWhere this shows up in practice
Other people the standard was written for.
People With Vestibular Disorders and Motion Sensitivity
Parallax, autoplay video, and large scroll-triggered animation can make someone physically ill. The fix is one media query.
Read the profilePeople With Photosensitive Epilepsy
The smallest affected group and the highest-severity consequence on this entire list. There is no partial credit here.
Read the profileAll 55 Success Criteria
Every Level A and AA criterion in plain language, with the failure we see most often for each.
Reference