[ { "id": "D01", "title": "Do not invent a strange dyslexia alphabet", "grade": "A", "scope": "dyslexia specific", "finding": "A 2026 meta-analysis of 15 studies and 688 dyslexic readers found no reliable overall reading advantage for specialist dyslexia fonts as a category.", "decision": "Keep familiar, socially neutral letter skeletons. Do not use heavy bottoms, arbitrary rotation, irregular baselines, or novelty merely to signal dyslexia.", "implementation": "Both Harmonia and High Speed use familiar, socially neutral skeletons. High Speed increases local distinction without heavy bottoms, irregular baselines or decorative disability cues.", "sources": [ "E002", "E019", "E020" ] }, { "id": "D02", "title": "Preserve familiar orthographic forms", "grade": "A/B", "scope": "dyslexia specific plus design inference", "finding": "Orthographic knowledge is an important component of reading, and unusual specialist letterforms have not reliably improved passage reading.", "decision": "Increase distinction locally instead of redesigning every glyph.", "implementation": "Harmonia prioritizes familiar forms. High Speed provides stronger alternative silhouettes as a separate explicit family rather than hidden contextual alternates.", "sources": [ "E005", "E020", "E061" ] }, { "id": "D03", "title": "Protect open apertures and counters", "grade": "A", "scope": "general visual recognition", "finding": "Controlled experiments show more identification errors when apertures are closed.", "decision": "Keep c, e, r, s, f and t open, including in heavier weights.", "implementation": "Both Reading families protect open internal white space. High Speed further emphasizes selected openings only where recognition benefits from clearer silhouette separation.", "sources": [ "E078" ] }, { "id": "D04", "title": "Use moderate weight, never extremes", "grade": "A", "scope": "general visual recognition", "finding": "Very thin and extremely bold strokes reduce recognition; moderate additional boldness helps more at smaller visual angles.", "decision": "Regular is the main reading weight. Medium is recommended for small screens or small visual sizes.", "implementation": "Light, Regular, Medium, SemiBold and Bold are included. Regular and Medium are the preferred starting points for sustained body reading; readers can compare weights in the Type Studio.", "sources": [ "E079" ] }, { "id": "D05", "title": "Use low stroke contrast", "grade": "B", "scope": "general typography", "finding": "Controlled research shows performance depends on stroke contrast as well as serif presence.", "decision": "Keep the approved low-contrast sans structure.", "implementation": "The family remains visually clean and consistent rather than introducing high-contrast display strokes.", "sources": [ "E080", "E050" ] }, { "id": "D06", "title": "Widen reading forms subtly, not globally", "grade": "B", "scope": "general visual recognition", "finding": "Wider letters improved parafoveal and peripheral letter recognition, while other work shows width also changes eye-movement strategy.", "decision": "Create a separate Reading cut with restrained width increases.", "implementation": "Each family has a dedicated Reading cut with calmer text proportions and a tighter Display cut for larger typography. The cuts are explicit font files rather than synthetic browser transforms.", "sources": [ "E081", "E062" ] }, { "id": "D07", "title": "Treat letter spacing and word spacing as one system", "grade": "A", "scope": "dyslexia specific", "finding": "Increasing letter spacing without adequate word spacing can slow reading, and spacing can explain apparent specialist-font advantages.", "decision": "Avoid extreme tracking. Preserve strong word boundaries.", "implementation": "Built in spacing remains moderate. The website Type Studio exposes additional letter spacing for reader controlled comparison rather than forcing exaggerated tracking into every setting.", "sources": [ "E016", "E017", "E018", "E047" ] }, { "id": "D08", "title": "Increase word boundary salience cautiously", "grade": "B", "scope": "dyslexia specific", "finding": "A 2024 study reported improved comprehension and fewer migration errors with increased inter-word spacing in students with dyslexia.", "decision": "Increase word spacing modestly while retaining normal word texture.", "implementation": "Word boundaries are kept clearly visible while letter spacing remains restrained. Word spacing is independently adjustable in the Type Studio.", "sources": [ "E077", "E016" ] }, { "id": "D09", "title": "Crowding matters, but more spacing is not a cure", "grade": "A", "scope": "dyslexia specific", "finding": "Crowding and spacing studies are mixed; some readers benefit, while other studies show no general speed or comprehension benefit from wider spacing.", "decision": "Keep spacing moderate and make future personalization possible.", "implementation": "Reading cut is a strong default, not an extreme dyslexia preset.", "sources": [ "E013", "E014", "E015", "E047", "E003" ] }, { "id": "D10", "title": "Keep I, l, 1 and i separable", "grade": "B", "scope": "recognition focused design inference", "finding": "Distinctive forms can improve isolated letter identification even when passage benefits are not guaranteed.", "decision": "Strengthen high-risk local distinctions without making the alphabet unfamiliar.", "implementation": "Harmonia keeps calm familiar I, l, 1 and i forms. High Speed increases local silhouette differences while preserving the overall visual language.", "sources": [ "E020", "E082" ] }, { "id": "D11", "title": "Offer stronger a and o separation through explicit family choice", "grade": "B/C", "scope": "personalization hypothesis", "finding": "A more differentiated a may improve local recognition for some readers, but unfamiliar orthographic forms can impose a familiarity cost.", "decision": "Keep Harmonia familiar, and expose stronger a and o silhouette separation in High Speed as an explicit family choice rather than a hidden alternate.", "implementation": "The stronger recognition treatment is exposed as the High Speed family. It is a visible family choice, not a hidden OpenType switch.", "sources": [ "E005", "E020", "E082" ] }, { "id": "D12", "title": "Differentiate O and 0 through structure, not decoration", "grade": "B", "scope": "general recognition", "finding": "Alphanumeric confusability matters, but slash-zero can collide conceptually with Ø in supported languages.", "decision": "Use proportion and construction to separate O and 0. Do not rely on an unusual default slash, dot or decorative mark merely to signal accessibility.", "implementation": "Harmonia differentiates O and 0 through proportion and construction. High Speed increases the distinction structurally while preserving a professional texture.", "sources": [ "E082" ] }, { "id": "D13", "title": "Do not distort b d p q around reversal folklore", "grade": "A/B", "scope": "dyslexia theory guardrail", "finding": "The evidence does not support treating letter reversal as the universal cause of dyslexia, and specialist letter-shape novelty does not reliably improve passage reading.", "decision": "Keep directional forms conventional and distinct through normal typographic cues.", "implementation": "No heavy bottoms, rotation or dramatic asymmetry is forced on b d p q.", "sources": [ "E002", "E019", "E020" ] }, { "id": "D14", "title": "Protect rn and vv from accidental merging", "grade": "B", "scope": "crowding inference", "finding": "Local crowding and letter proximity can impair identification even when more global spacing is not beneficial.", "decision": "Use pair-specific protection rather than global tracking.", "implementation": "Potential rn and m collisions are handled through width, shoulder construction and spacing, with stronger separation in High Speed.", "sources": [ "E013", "E078" ] }, { "id": "D15", "title": "Use enough effective visual size", "grade": "A", "scope": "dyslexia specific plus vision science", "finding": "Dyslexic children can require larger critical print sizes, and reading speed depends strongly on visual angle near the critical threshold.", "decision": "Do not compensate for undersized text with gimmicks.", "implementation": "Reading guidance prioritizes adequate size; Medium weight is available for smaller text.", "sources": [ "E021", "E022", "E051" ] }, { "id": "D16", "title": "Protect word-initial clarity", "grade": "B", "scope": "dyslexia specific emerging evidence", "finding": "Parafoveal studies suggest altered early letter-position processing, and recent gaze-contingent work reports greater foveal load in dyslexic children.", "decision": "Keep word-initial glyphs simple and recognizable.", "implementation": "No decorative entry strokes or contextual novelty at word beginnings.", "sources": [ "E034", "E036", "E037", "E043" ] }, { "id": "D17", "title": "Use an optical family instead of one fixed geometry", "grade": "A/B", "scope": "evidence synthesis", "finding": "Legibility varies by reading scenario; no single typeface geometry is universally optimal.", "decision": "Separate aesthetic large-text needs from continuous-reading needs.", "implementation": "Harmonia and High Speed each provide dedicated Reading and Display cuts across five weights with upright and italic styles.", "sources": [ "E082", "E056" ] }, { "id": "D18", "title": "Do not use mandatory ligatures", "grade": "B", "scope": "conservative design inference", "finding": "The product prioritizes explicit grapheme identity and local character recognition.", "decision": "Avoid automatically merging visible letters in the Reading cut.", "implementation": "Standard reading CSS disables optional ligatures for body text.", "sources": [ "E020", "E061" ] }, { "id": "D19", "title": "Punctuation must remain visible", "grade": "B", "scope": "general reading design", "finding": "Reading is not only letter recognition; segmentation and navigation cues should remain visible at text sizes.", "decision": "Keep punctuation optically visible and rhythmically consistent at reading sizes without novelty enlargement.", "implementation": "Punctuation is kept optically visible and rhythmically consistent in both Reading cuts without novelty enlargement.", "sources": [ "E082" ] }, { "id": "D20", "title": "Publish only audited diacritic and language coverage", "grade": "A technical", "scope": "multilingual engineering", "finding": "A font cannot claim multilingual support if stacked marks clip or combine incorrectly.", "decision": "Treat diacritics as first class reading information and limit language claims to the audited character repertoire.", "implementation": "The published release contains broad precomposed Latin coverage plus combining mark glyphs. Language support claims are limited to the audited repertoire and do not imply complete script shaping for unsupported writing systems.", "sources": [ "E026", "E027" ] }, { "id": "D21", "title": "Do not prescribe color as dyslexia treatment", "grade": "A", "scope": "dyslexia specific", "finding": "Systematic-review evidence does not support colored overlays as a general dyslexia treatment.", "decision": "Offer theme choice for comfort, not therapeutic claims.", "implementation": "Website supports light and dark themes; the font itself remains color neutral.", "sources": [ "E025", "E055" ] }, { "id": "D22", "title": "No Bionic-style prefix bolding", "grade": "A", "scope": "direct experimental evidence", "finding": "Controlled eye-movement research found no reading benefit and costs from bolding the first part of every word.", "decision": "Do not build prefix bolding into the font or reading system.", "implementation": "Bold is reserved for normal semantic hierarchy.", "sources": [ "E063" ] }, { "id": "D23", "title": "Treat eye movements as outcomes, not causes", "grade": "A", "scope": "dyslexia specific", "finding": "Dyslexic readers often show different reading eye movements, but basic oculomotor function can be normal and lexical difficulty strongly modulates gaze.", "decision": "Use gaze as a validation signal, not as a mythology for glyph design.", "implementation": "Human validation protocol measures gaze optionally alongside accuracy, comprehension and effort.", "sources": [ "E023", "E024", "E039", "E047" ] }, { "id": "D24", "title": "Make personalization granular instead of strange by default", "grade": "C", "scope": "product hypothesis", "finding": "Dyslexia and visual-attention profiles are heterogeneous across readers and languages.", "decision": "Keep strong defaults while exposing meaningful controls that correspond to real shipping font files and normal typographic variables.", "implementation": "Personalization is primarily explicit: Harmonia or High Speed family, Reading or Display cut, weight, size, letter spacing, word spacing and line height. The website makes these controls directly testable.", "sources": [ "E004", "E035", "E056", "E058" ] } ]