Do’s & Don’ts: 6 Fonts That Break Arabic and Thai Layouts

Why Arabic and Thai Are High-Risk Scripts Top Font-Based Failures That Break UX Fonts Commonly Responsible for Failures Real Case Study: Thai Public Sector Accessibility Failure Where MoniSa Stands: QA Beyond the Font Dropdown Typography QA Checklist for Global Teams Final Word: Don’t Let Fonts Be Your Weakest Link Why MoniSa? Ready to Audit Your Fonts? Typography Is Not Universal. It’s Script-Specific. Fonts can make or break the global user experience. What looks clean and professional in English might render disastrously in Arabic or Thai. From broken ligatures and illegible diacritics to spacing failures and regulatory non-compliance, typography is not just a design layer. It is a functional cornerstone of multilingual content integrity. As the world grows more multilingual, digital products must meet not only translation accuracy but also script fidelity. Arabic and Thai, in particular, pose intricate rendering challenges that require typographic and linguistic expertise working hand in hand. At MoniSa Enterprise, we go beyond basic font checks. We integrate ISO-certified font QA into every step of your multimedia and localization pipeline, ensuring every script reads as beautifully as it looks. Why Arabic and Thai Are High-Risk Scripts Both Arabic and Thai pose unique challenges because they do not follow Latin-script logic. Arabic Typography: Complex, Cursive, Contextual Right-to-left directionality Cursive flow with contextual joining of characters Ligature dependence for visual and grammatical clarity Diacritic use for pronunciation and disambiguation Arabic script is not just a set of characters, but a fluid writing system. Each character has multiple forms depending on its position in a word. The connection between characters is essential to meaning and readability. Fonts that do not account for contextual shaping logic often display broken joins or substitute letters with their isolated forms, disrupting readability entirely. Common Failures in Arabic: Characters rendered as disjointed shapes instead of connected script Diacritics placed randomly above or below the baseline Lack of ligature substitution creates a staccato reading rhythm Inadequate RTL support breaks line layout and justification Thai Typography: Vertical Logic Meets Minimal Spacing No spacing between words Tone marks and vowel signs placed above, below, and around base consonants Tight vertical grid with strict alignment rules Line height must be exact to prevent overlap or truncation Thai typography is governed by complex placement rules, where a single consonant may carry up to three diacritics in various directions. Without precise stacking logic and correct vertical metrics, tone marks can merge, float, or even fall outside text containers, making reading difficult or impossible. Common Failures in Thai: Vowel marks split across line breaks Tone marks placed too high or too low, clashing with surrounding glyphs Vertical overlap of stacked diacritics Text cut off in mobile or compressed environments Top Font-Based Failures That Break UX Broken Character Joins (Arabic) Outdated or rigid fonts fail to execute contextual shaping logic, displaying isolated glyphs where connections should exist. Overlapping Diacritics (Arabic and Thai) Incorrect stacking order or insufficient glyph space causes tone marks and vowels to collide with adjacent characters. Misaligned Tone Marks (Thai) Tone marks appear too far from their intended consonant, especially in bold or italic font weights. Excessive or Inconsistent Line Heights Improper font metrics either compress glyphs vertically, leading to collisions, or introduce large gaps that disrupt content flow. Justification Glitches (Arabic) Justified paragraphs can stretch Arabic characters unnaturally, altering meaning or creating a broken visual rhythm. Platform-Based Rendering Variability Fonts that look acceptable in Word or Figma may break on Android or iOS. Inconsistency across platforms introduces untestable risk. Source : Do’s & Don’ts: 6 Fonts That Break Arabic and Thai Layouts