Does letter spacing help dyslexia? What the research says

October is Dyslexia Awareness Month, and every year it brings a fresh round of posts about special fonts. The research tells a quieter and more useful story. The thing that seems to help many dyslexic readers is not the shape of the letters. It is the space between them.

What the study found

In 2012, a team of researchers tested a very simple change on a large group of Italian and French children with dyslexia: they printed the same text with extra-large spacing between the letters. With no training at all, the children's reading performance improved substantially, on the spot (Zorzi et al., PNAS, 2012).

The researchers link the effect to crowding: a perceptual effect where nearby letters interfere with recognising each one. Everyone experiences crowding to some degree, but dyslexic readers are abnormally affected by it, and crowding is modulated by the spacing between letters. Put the letters further apart and there is less interference to fight through.

So what about dyslexia fonts?

Specialised fonts such as Dyslexie and OpenDyslexic change the shapes of the letters, and they also tend to come with wider spacing. Two studies help separate those two things.

When low-progress readers read in the Dyslexie font, they read about 7% more words per minute than in standard Arial. But when the researchers gave Arial the same letter and word spacing as Dyslexie, the difference was no longer significant. Their conclusion: the benefit came from the spacing, not the specially designed letter shapes (Marinus et al., Dyslexia, 2016).

For OpenDyslexic, a study with elementary students with dyslexia found no improvement in reading rate or accuracy compared with Arial and Times New Roman, and none of the children said they preferred it (Wery & Diliberto, Annals of Dyslexia, 2017). We go through the font question in more detail in does the OpenDyslexic font really help?

Put together, the practical message is simple. If a special font helps your child, keep using it. But you do not need one. Spacing is something you can change in almost any app, for free.

What spacing will not do

Spacing is not a treatment for dyslexia, and no one in this research claims it is. It does not teach a child to decode words. What it does is make each page less of a fight. That matters more than it sounds: as the 2012 researchers point out, reading more is the most efficient intervention for dyslexia, and a child who finds reading exhausting reads less. Anything that makes the page easier to face means more reading.

It also will not suit every child. Some readers find very wide spacing breaks words apart too much. That is why the best test is your child's own reaction.

How to try it tonight

• Take tonight's reading and show it two ways: as it is, and with wider letter spacing, wider line spacing and slightly bigger text.
• Ask which one is easier. Believe the answer. Most children know within a line.
• Keep the lines short. A narrow column is easier to track than a line running the width of a laptop screen.
• Print it spaced. For worksheets you print at home, the same settings work on paper, and the school may be able to do the same if you ask.
• Try a tint. Some readers prefer a cream or pale background to bright white. There is less research here, so treat it as preference, not treatment.

In a word processor, letter spacing is usually under the font's advanced settings (often called character spacing). In a browser, Edge's Reading mode lets you change the font, text size and column width. Or paste the text into the Versed easy reader, which widens the spacing, enlarges the type, adds a tint and puts a line ruler under the line they are on.

Spacing plus listening

For long texts in other subjects, spacing works well alongside a read-aloud tool, so your child can listen and follow the words at the same time. We compared the free options, most of which are already on your devices, in free read-aloud tools for dyslexia.

References

• Zorzi, M., Barbiero, C., Facoetti, A., Lonciari, I., Carrozzi, M., Montico, M., Bravar, L., George, F., Pech-Georgel, C., & Ziegler, J. C. (2012). Extra-large letter spacing improves reading in dyslexia. PNAS, 109(28), 11455–11459.
• Marinus, E., Mostard, M., Segers, E., Schubert, T. M., Madelaine, A., & Wheldall, K. (2016). A special font for people with dyslexia: Does it work and, if so, why? Dyslexia, 22(3), 233–244.
• Wery, J. J., & Diliberto, J. A. (2017). The effect of a specialized dyslexia font, OpenDyslexic, on reading rate and accuracy. Annals of Dyslexia, 67(2), 114–127.