Effectiveness of fonts for dyslexic is not yet proven…
Use a special font can mitigate the effects of dyslexia, a specific reading disorder that affects almost 10% of the world population. But what font choose ?
Dyslexic people are hampered in their reading because they are struggling to correctly identify letters, syllables or words. So we recommend them to use fonts whose characters are clearly identifiable, in order to reduce errors of reading and facilitate their understanding of the texts.
Often recommended fonts : sans-serif
Traditionally recommended fonts for easy reading are sans-serif fonts like Arial, Tahoma et Verdana.
In school context, Century Gothic is recommended for learning to write. The form of the Myriad Pro, a modern font designed by Adobe, is also recommended, as well as Trebuchet MS. But for dyslexic people who mentally reverse letters, they have a too regular drawing.
Some dyslexic people find that Comic Sans, originally designed for children, is one of the most readable Windows fonts commonly available. Others find it too oily, too childish or too informal.
Special dys fonts
Often recommended for dyslexic adopted for Montessori materials, Sassoon was in fact designed for early reading. Tiresias was designed for visually impaired. It has good readability, but it does not care about the specific dyslexic confusions. Andika was clearly designed for a literary use for young readers and is adapted for dyslexic children.
Research in the field of typography to help dyslexic children are very recent. In recent years, new fonts are specifically designed for dyslexic. They are designed to reduce reading errors by facilitating character recognition. They are distinguished by the letters’ shape :
- asymmetry of the « b » et « d », « p » and « q » letters ;
- distinction between lowercase “l”, capital “I” and the number “1” ;
- sufficient character’s width to avoid confusion between “rn” and the “m” letter ;
- good ascenders (of b, d, f, h, k, l, t, and all upercase) and descending jambs (of g, j, p, q, y) ;
- « g » and « a » letters similar to handwriting…
Among them Read Regular is designed to help dyslexic people to read and write more easily. Based on Comic Sans, Lexia Readable is a font family designed for maximum readability, even in small text. Sylexiad is designed for dyslexic adults.
The aptly named Dyslexie is a recent font, built on Comic Sans, by a dyslexic graphic designer, and seems “extremely well received by people with dyslexia.” Finally, based on Bitstream Vera, OpenDyslexic is a free font easy to use.
Uncertain effectiveness of those fonts
Studies on the effectiveness of specific fonts for dyslexic people are recent (since 2005) and expose contradictory or not decisive results. The last study that compares multiple fonts , common and special, including the OpenDyslexic, reports that the best fonts for dyslexics are Helvetica, Courier, Arial and Verdana… like for other readers ! Fonts specifically designed for dyslexics are sometimes heavily criticized.
In short, there is no concrete marker of any font on improving reading speed and comprehension for dyslexics : much variability and few recommendations. Promote sans-serif fonts but remember that, among them, there is not particularly recommended font for dyslexic people. So, on the Web, simply make sure to leave everyone the opportunity to apply the font he prefer.
Whatever, dyslexic people are more than others sensitive to font size, length of lines and justification. These aspects are indeed the only ones to be recommended, particularly to improve accessibility (see : Améliorer la lisibilité typographique). In particular, children prefer “lighter” and “spaced” texts, with “very black” letters . More than the choice of font, macrotypographie (layout, margins, spaces and contrasts) is what brings the better help.