Multilingual, Plain Japanese (“Yasashii Nihongo”), and Accessibility: A Web Design Guide that Communicates Across Language Tags, Translation, Terminology Consistency, Screen Reading, and Cultural Differences (WCAG 2.1 AA)
Summary (Key Points Up Front)
- Multilingual support isn’t complete just by “providing translations.” It becomes accessible only when you include language attributes (
lang), plain wording, consistent terminology, number/date/address formats, and screen-reader behavior.- “Yasashii Nihongo” (plain Japanese) isn’t only for non-native speakers. It improves understandability accessibility for many situations—older adults, children, learning disabilities, fatigue, and emergencies.
- Without proper
langswitching, screen readers may mispronounce English and proper nouns, seriously harming comprehension.- In translation, clarity of purpose and action matters more than literalness. Forms, errors, and procedural guidance need special care.
- This guide includes plain-language rewrite examples, UI text templates,
langimplementation snippets, a translation workflow, and a checklist.Who this is for: municipal/public websites, hospitals/schools/transport/disaster communication teams, global web operations, UI/UX designers, translation coordinators, front-end engineers, editors
Accessibility target: WCAG 2.1 AA (especially 3.1.x Language, 3.3.x Input Assistance, 1.3.1 Structure, 2.4.x Navigation)
1. Introduction: If the Words Don’t Get Through, Accessibility Isn’t Finished
We’ve improved many “forms” of accessibility—color, typography, keyboard operation, forms, PDFs, ARIA, and more. But even if something is operable and readable aloud, users can’t reach their goal if they can’t understand the words.
This matters most for high-stakes content—procedures, healthcare, education, disaster response, hiring, administrative services—where failure isn’t acceptable. In such contexts, difficult language becomes a literal “can’t use it” barrier.
This article organizes practical design, implementation, and operations for web communication that lands, centered on multilingual support and Yasashii Nihongo (plain Japanese).
2. WCAG Viewpoint: Language Has Two Pillars—“Declaration” and “Understanding”
2.1 Declaring Language (Language of Page / Parts)
- Whole page:
<html lang="ja"> - Switching within a page:
<span lang="en">etc.
Without this, screen readers can apply the wrong pronunciation rules, making proper nouns and English loanwords hard to understand.
Implementation example (whole page)
<!doctype html>
<html lang="ja">
<head>…</head>
<body>…</body>
</html>
Implementation example (partial switch)
<p>This service supports <span lang="en">Single Sign-On</span>.</p>
2.2 Supporting “Understanding” (Reading Level / Clear Language)
In WCAG 2.1, reading-level guidance leans toward AAA, but in practice many teams aim for AA while adopting plain phrasing, consistent terminology, and structures that reduce misunderstanding.
Especially for form errors and procedures, supporting understanding directly raises completion rates.
3. Yasashii Nihongo: “Understandability Accessibility” That Helps Everyone
Yasashii Nihongo doesn’t mean “childish vocabulary.”
The core is: short, concrete, one idea per sentence, and actions are clear.
3.1 Practical Rules (Real-World Version)
- Aim for 50–60 Japanese characters per sentence
- Keep subject and predicate close
- Avoid jargon; if needed, paraphrase
- Explain loanwords on first use (e.g., “Initial Settings (Default)”)
- Repeat key terms; don’t rotate synonyms
- Use numbered steps for procedures
- Avoid: double negatives, euphemisms, unclear subjects
3.2 Rewrite Examples
Before (hard)
“Your procedure may not have been completed. We kindly request that you verify this immediately.”
After (plain)
“The procedure may not be complete. Please check the screen now.”
Before (vague)
“Please respond as appropriate.”
After (specific)
“Please do one of the following: 1. Check your email 2. Contact support”
3.3 Disaster / Emergency Message Template (Especially Important)
Write in this order:
- When (time)
- Where (place)
- Who (target)
- What to do (action)
- How (method)
This stays understandable even under stress and confusion.
4. Multilingual UI Design: Create Japanese Source Text That’s Easy to Translate
Translation quality depends not only on translators, but heavily on how the source text is written.
4.1 Japanese That Translates Well (Translation-Ready Source)
- Don’t omit subjects too much
- Short sentences
- Avoid abbreviations (clarify what kind of “application” it is)
- Make objects explicit (“Submit” → “Submit documents”)
- Avoid culture-dependent metaphors (“makes sense” etc.)
4.2 Terminology Consistency
If the same concept is described in multiple ways, translations drift and users get lost. Examples:
- Don’t mix “Application / Registration” unless meanings are distinct
- Don’t mix “Login / Sign In / Enter”
Best practice is to fix terms in a glossary.
4.3 UI Copy Templates (Short, Actionable)
- Buttons: verb + object (e.g., “Confirm reservation”, “Save address”)
- Errors: cause + fix (e.g., “The email format is incorrect. Please enter it as shown in the example.”)
- Empty states: state + next action (e.g., “No reservations yet. Make a new reservation.”)
5. Numbers, Dates, Addresses, Currency: Where Cultural Differences Cause Misunderstanding
This is where multilingual projects often break.
5.1 Date Formats
- Japan: YYYY/MM/DD
- U.S.: MM/DD/YYYY
- Europe: DD/MM/YYYY
Confusion can cause serious errors. Mitigations: - Spell months (Jan/Feb…)
- Add ISO format (YYYY-MM-DD)
- Write months in words (e.g., “January 19, 2026”)
5.2 Address Order
Address formats differ by country. Either localize the field structure by country or at minimum show localized examples.
5.3 Thousands Separators and Decimals
- 1,000.50 (U.S.)
- 1.000,50 (Germany etc.)
Mitigation: localize display; assist input (format conversion) where possible.
6. Forms and Errors in Multiple Languages: The Most Important Area for Completion
6.1 Keep Errors Short—and Always Include How to Fix
Example (Japanese):
- “Please enter phone numbers using only digits. Example:09012345678”
Keep a consistent “sentence pattern” so translations preserve structure.
6.2 Use autocomplete and inputmode
These reduce input burden across languages:
autocomplete="email"autocomplete="postal-code"inputmode="numeric"
6.3 Labels and Screen Reading in Multiple Languages
When switching languages, update lang correctly so screen-reader pronunciation doesn’t mix awkwardly.
7. Implementation Essentials: Balancing Language Switching with SEO and Accessibility
7.1 Language Switch UI: Users Must Be Able to Return Anytime
- Fixed location (e.g., top-right in global nav)
- Show current language clearly (e.g., 日本語 / English)
- Keyboard operable
- Use
aria-currentto indicate the active language
7.2 Correct Page-Level Language
- Switch
langproperly - Titles/headings should also be in that language
- Avoid text baked into images; provide real text
7.3 Prepare for RTL (Right-to-Left) Languages
For Arabic and others, layout can fundamentally change. If there’s any chance you’ll support RTL, design with dir="rtl" in mind.
8. Translation Workflow: Balancing Quality and Accessibility
8.1 Recommended “Start Small” Flow
- Simplify the source (short sentences, consistent terms)
- Build a glossary (at least ~20 terms)
- Translate (human + review)
- Test on real devices (mobile, screen reader)
- Define update rules (source change → translation update deadline)
8.2 Where Machine Translation Fits
- Temporary use when speed matters
- Internal comprehension
But for public release, human review is essential—especially for: - Proper nouns
- Legal/medical/procedural text
- Warnings and cautions
9. Five-Minute Checklist: Minimum Verification for Multilingual + Plain Japanese
<html lang="…">is correct- English/proper nouns use partial
langwhere needed - Critical procedures are numbered and short
- Terminology is consistent (no login/sign-in mix, etc.)
- Dates/numbers/units avoid cross-cultural confusion
- Form errors follow “cause + fix”
- Language switch is keyboard operable and current language is obvious
- Avoid excessive text-in-images; equivalent text exists
10. Value for Each Audience (Concrete)
- Foreign residents / travelers: can understand procedures and take action
- Older adults: fewer difficult words, shorter sentences, less misunderstanding
- People with learning differences / cognitive traits: clearer steps and lower cognitive load
- Users in emergencies: actions become immediately clear
- Organizations: fewer inquiries, stronger accountability, more trust, more efficient translation updates
11. Accessibility Level: Where This Guide Lands
- Key WCAG 2.1 AA-related points covered:
- 3.1.1 Language of Page: setting
lang - 3.1.2 Language of Parts: switching
langfor English/proper nouns - 3.3.1 Error Identification / 3.3.3 Error Suggestion: understandable multilingual errors
- 1.3.1 Info and Relationships: structured steps/lists/headings
- 2.4.6 Headings and Labels: labels remain purpose-clear after translation
- 2.1.1 Keyboard: operable language switch
- 1.4.3 Contrast / 1.4.1 Use of Color: visibility maintained in multilingual UI
- 3.1.1 Language of Page: setting
- Yasashii Nihongo isn’t a strict AA requirement, but it is a highly practical measure that strongly supports Understandable and Operable outcomes.
12. Conclusion: Language Accessibility Widens Society’s Entrance
- Multilingual design includes not only translation, but
lang, terminology consistency, and formatting conventions. - Yasashii Nihongo helps not only non-native speakers, but people in many situations.
- Translation-ready source text stabilizes both quality and maintenance.
- Dates, numbers, addresses, and currency are high-risk for misunderstanding—always mitigate.
- Forms and errors are the top priority: state cause + fix so users don’t get lost.
- Protect quality after updates with checklists and operational rules.
Words are the door to information itself.
If you widen that door just a little, more people get through—and fewer people are left struggling.
May your site become a place that anyone in the world can “understand and do.”