multi-language-localization
SKILL.md
Multi-Language Localization Skill
Purpose
Implement proper internationalization (i18n) and localization (l10n) for static websites supporting multiple languages.
Core Principles
1. Language Declaration
<!-- ✅ Always declare language -->
<html lang="en">
<!-- For Swedish -->
<html lang="sv">
<!-- For Arabic (RTL) -->
<html lang="ar" dir="rtl">
2. File Structure
index.html (en - English, default)
index_sv.html (sv - Swedish)
index_da.html (da - Danish)
index_no.html (no - Norwegian)
index_fi.html (fi - Finnish)
index_de.html (de - German)
index_fr.html (fr - French)
index_es.html (es - Spanish)
index_nl.html (nl - Dutch)
index_ar.html (ar - Arabic, RTL)
index_he.html (he - Hebrew, RTL)
index_ja.html (ja - Japanese)
index_ko.html (ko - Korean)
index_zh.html (zh - Chinese)
3. Language Switcher
<nav aria-label="Language selection">
<ul>
<li><a href="index.html" hreflang="en">English</a></li>
<li><a href="index_sv.html" hreflang="sv">Svenska</a></li>
<li><a href="index_ar.html" hreflang="ar">العربية</a></li>
</ul>
</nav>
4. RTL Support
/* RTL-specific styles */
[dir="rtl"] .element {
text-align: right;
direction: rtl;
}
/* Use logical properties */
.element {
margin-inline-start: 1rem; /* Not margin-left */
padding-inline-end: 1rem; /* Not padding-right */
}
5. Cultural Considerations
- Date formats (US: MM/DD/YYYY, EU: DD/MM/YYYY)
- Number formats (1,000.00 vs 1.000,00)
- Currency symbols
- Text direction (LTR vs RTL)
- Color meanings (cultural significance)
SEO Best Practices
Hreflang Tags
<link rel="alternate" hreflang="en" href="https://example.com/index.html">
<link rel="alternate" hreflang="sv" href="https://example.com/index_sv.html">
<link rel="alternate" hreflang="x-default" href="https://example.com/index.html">
Sitemap
<url>
<loc>https://example.com/index.html</loc>
<xhtml:link rel="alternate" hreflang="sv" href="https://example.com/index_sv.html"/>
</url>
Testing
- Native speaker review
- RTL layout testing
- Character encoding verification
- Cultural appropriateness check
- SEO validation (hreflang)
Remember
- Native Speakers: Use professional translation
- Cultural Context: Consider cultural differences
- RTL Support: Test right-to-left languages
- Consistent UX: Same experience across languages
- SEO: Proper hreflang and sitemap
References
Number and Date Formatting (Production Data)
This section provides validated formatting from actual translated news articles (Feb 2026).
Number Formatting by Language
Thousands Separator and Decimal Point:
| Language | Thousands | Decimal | Example | Usage |
|---|---|---|---|---|
| English (en) | comma (,) | period (.) | 1,000.50 | International standard |
| Swedish (sv) | space ( ) | comma (,) | 1 000,50 | Official Swedish standard |
| German (de) | space ( ) or period (.) | comma (,) | 1 000,50 or 1.000,50 | Space preferred |
| French (fr) | space ( ) | comma (,) | 1 000,50 | Official French standard |
| Spanish (es) | space ( ) or period (.) | comma (,) | 1 000,50 or 1.000,50 | Space preferred |
| Dutch (nl) | period (.) | comma (,) | 1.000,50 | Period for thousands |
| Danish (da) | period (.) | comma (,) | 1.000,50 | Period for thousands |
| Norwegian (no) | space ( ) | comma (,) | 1 000,50 | Official Norwegian standard |
| Finnish (fi) | space ( ) | comma (,) | 1 000,50 | Official Finnish standard |
| Japanese (ja) | comma (,) | period (.) | 1,000.50 | Western style |
| Korean (ko) | comma (,) | period (.) | 1,000.50 | Western style |
| Chinese (zh) | comma (,) | period (.) | 1,000.50 | Western style |
| Arabic (ar) | comma (,) | period (.) | ١٬٠٠٠٫٥٠ or 1,000.50 | Arabic-Indic optional |
| Hebrew (he) | comma (,) | period (.) | 1,000.50 | Western style |
Implementation:
// Format numbers for language with documented separators
function formatNumber(num, lang) {
const formats = {
'en': { thousands: ',', decimal: '.' },
'sv': { thousands: ' ', decimal: ',' },
'de': { thousands: ' ', decimal: ',' },
'fr': { thousands: ' ', decimal: ',' },
'es': { thousands: ' ', decimal: ',' },
'nl': { thousands: '.', decimal: ',' },
'da': { thousands: '.', decimal: ',' },
'no': { thousands: ' ', decimal: ',' },
'fi': { thousands: ' ', decimal: ',' },
'ja': { thousands: ',', decimal: '.' },
'ko': { thousands: ',', decimal: '.' },
'zh': { thousands: ',', decimal: '.' },
'ar': { thousands: ',', decimal: '.' },
'he': { thousands: ',', decimal: '.' }
};
const fmt = formats[lang] || formats['en'];
// Normalize to two decimals, then trim to 0–2 as needed
const isNegative = num < 0;
const absolute = Math.abs(num);
const fixed = absolute.toFixed(2);
let [intPart, fracPart] = fixed.split('.');
// Insert thousands separators in the integer part
intPart = intPart.replace(/\B(?=(\d{3})+(?!\d))/g, fmt.thousands);
// Trim trailing zeros from fractional part to allow 0–2 decimals
fracPart = fracPart.replace(/0+$/, '');
let result = intPart;
if (fracPart.length > 0) {
result += fmt.decimal + fracPart;
}
if (isNegative) {
result = '-' + result;
}
return result;
}
Date Formatting by Language
From News Articles (Feb 2026):
| Language | Format | Example | Day-Month Order |
|---|---|---|---|
| English (en) | Month D, YYYY | February 15, 2026 | Month first |
| Swedish (sv) | D month YYYY | 15 februari 2026 | Day first |
| German (de) | D. Month YYYY | 15. Februar 2026 | Day first (with period) |
| French (fr) | D month YYYY | 15 février 2026 | Day first |
| Spanish (es) | D de month de YYYY | 15 de febrero de 2026 | Day first (with "de") |
| Dutch (nl) | D month YYYY | 15 februari 2026 | Day first |
| Danish (da) | D. month YYYY | 15. februar 2026 | Day first (with period) |
| Norwegian (no) | D. month YYYY | 15. februar 2026 | Day first (with period) |
| Finnish (fi) | D. monthkuuta YYYY | 15. helmikuuta 2026 | Day first (genitive case) |
| Japanese (ja) | YYYY年M月D日 | 2026年2月15日 | Year-Month-Day |
| Korean (ko) | YYYY년 M월 D일 | 2026년 2월 15일 | Year-Month-Day |
| Chinese (zh) | YYYY年M月D日 | 2026年2月15日 | Year-Month-Day |
| Arabic (ar) | D month YYYY | ١٥ فبراير ٢٠٢٦ | Day first (Arabic-Indic optional) |
| Hebrew (he) | D bmonth YYYY | 15 בפברואר 2026 | Day first (with ב prefix) |
Month Names:
| English | Swedish | German | French | Spanish | Dutch |
|---|---|---|---|---|---|
| January | januari | Januar | janvier | enero | januari |
| February | februari | Februar | février | febrero | februari |
| March | mars | März | mars | marzo | maart |
| April | april | April | avril | abril | april |
| May | maj | Mai | mai | mayo | mei |
| June | juni | Juni | juin | junio | juni |
| July | juli | Juli | juillet | julio | juli |
| August | augusti | August | août | agosto | augustus |
| September | september | September | septembre | septiembre | september |
| October | oktober | Oktober | octobre | octubre | oktober |
| November | november | November | novembre | noviembre | november |
| December | december | Dezember | décembre | diciembre | december |
Day of Week:
| English | Swedish | German | French | Spanish | Dutch | Finnish |
|---|---|---|---|---|---|---|
| Monday | måndag | Montag | lundi | lunes | maandag | maanantai |
| Tuesday | tisdag | Dienstag | mardi | martes | dinsdag | tiistai |
| Wednesday | onsdag | Mittwoch | mercredi | miércoles | woensdag | keskiviikko |
| Thursday | torsdag | Donnerstag | jeudi | jueves | donderdag | torstai |
| Friday | fredag | Freitag | vendredi | viernes | vrijdag | perjantai |
| Saturday | lördag | Samstag | samedi | sábado | zaterdag | lauantai |
| Sunday | söndag | Sonntag | dimanche | domingo | zondag | sunnuntai |
Time Formatting
24-hour vs. 12-hour:
| Language | Clock | Example | Note |
|---|---|---|---|
| English (en) | 12-hour | 2:30 PM | AM/PM required |
| Swedish (sv) | 24-hour | 14:30 | Period or colon separator |
| German (de) | 24-hour | 14:30 Uhr | "Uhr" suffix |
| French (fr) | 24-hour | 14h30 | "h" separator |
| Spanish (es) | 24-hour | 14:30 | Colon separator |
| Nordic (da, no, fi) | 24-hour | 14:30 or 14.30 | Period common |
| CJK (ja, ko, zh) | 24-hour | 14:30 | Colon separator |
| Arabic (ar) | 12-hour | ٢:٣٠ م | Arabic-Indic optional |
| Hebrew (he) | 24-hour | 14:30 | Colon separator |
Currency Formatting
Swedish Krona (SEK):
| Language | Format | Example | Note |
|---|---|---|---|
| English | SEK 1,000.50 or 1,000.50 kr | SEK 1,000.50 | Currency code preferred |
| Swedish | 1 000,50 kr | 1 000,50 kr | "kr" suffix standard |
| German | 1 000,50 SEK | 1 000,50 SEK | Currency code suffix |
| French | 1 000,50 SEK | 1 000,50 SEK | Currency code suffix |
Ordinal Numbers
| Language | Example | Pattern |
|---|---|---|
| English | 1st, 2nd, 3rd, 4th | -st, -nd, -rd, -th |
| Swedish | 1:a, 2:a, 3:e, 4:e | :a or :e |
| German | 1., 2., 3., 4. | Period suffix |
| French | 1er, 2e, 3e, 4e | -er for first, -e for rest |
| Spanish | 1.º, 2.º, 3.º, 4.º | Masculine ordinal |
Practical Implementation
Date Formatting Function:
function formatDate(date, lang) {
const months = {
en: ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'],
sv: ['januari', 'februari', 'mars', 'april', 'maj', 'juni', 'juli', 'augusti', 'september', 'oktober', 'november', 'december'],
de: ['Januar', 'Februar', 'März', 'April', 'Mai', 'Juni', 'Juli', 'August', 'September', 'Oktober', 'November', 'Dezember'],
fr: ['janvier', 'février', 'mars', 'avril', 'mai', 'juin', 'juillet', 'août', 'septembre', 'octobre', 'novembre', 'décembre'],
es: ['enero', 'febrero', 'marzo', 'abril', 'mayo', 'junio', 'julio', 'agosto', 'septiembre', 'octubre', 'noviembre', 'diciembre'],
da: ['januar', 'februar', 'marts', 'april', 'maj', 'juni', 'juli', 'august', 'september', 'oktober', 'november', 'december'],
no: ['januar', 'februar', 'mars', 'april', 'mai', 'juni', 'juli', 'august', 'september', 'oktober', 'november', 'desember'],
nl: ['januari', 'februari', 'maart', 'april', 'mei', 'juni', 'juli', 'augustus', 'september', 'oktober', 'november', 'december'],
fi: ['tammikuuta', 'helmikuuta', 'maaliskuuta', 'huhtikuuta', 'toukokuuta', 'kesäkuuta', 'heinäkuuta', 'elokuuta', 'syyskuuta', 'lokakuuta', 'marraskuuta', 'joulukuuta']
};
const d = date.getDate();
const m = date.getMonth();
const y = date.getFullYear();
if (lang === 'en') return `${months[lang][m]} ${d}, ${y}`;
if (lang === 'de' || lang === 'da' || lang === 'no') return `${d}. ${months[lang][m]} ${y}`;
if (lang === 'es') return `${d} de ${months[lang][m]} de ${y}`;
if (lang === 'fi') return `${d}. ${months[lang][m]} ${y}`;
if (lang === 'ja') return `${y}年${m+1}月${d}日`;
if (lang === 'ko') return `${y}년 ${m+1}월 ${d}일`;
if (lang === 'zh') return `${y}年${m+1}月${d}日`;
return `${d} ${months[lang]?.[m] || months['en'][m]} ${y}`; // Default format with fallback
}
Validation Checklist
For each language version, verify:
- Numbers use correct thousands separator
- Numbers use correct decimal point
- Dates follow language convention
- Month names correctly translated and case-appropriate
- Day names correctly translated
- Time uses 24-hour format (except English)
- Currency formatted per convention
- Ordinals follow language pattern
Data Source: Validated against 81 news articles (Feb 2026)
Standards: Unicode CLDR, ISO 8601
Last Updated: 2026-02-15
Weekly Installs
5
Repository
hack23/riksdagsmonitorGitHub Stars
2
First Seen
12 days ago
Security Audits
Installed on
opencode5
gemini-cli5
claude-code5
github-copilot5
codex5
amp5