name	i18n
description	Write internationalization-friendly HTML pages. Use when creating multilingual content, setting lang attributes, handling RTL languages, or preparing content for translation.
allowed-tools	Read, Write, Edit

Internationalization (i18n) Skill

This skill ensures HTML pages are properly structured for internationalization and localization.

Essential Attributes

The `lang` Attribute (REQUIRED)

Every HTML document MUST have a language declaration:

<html lang="en">

Use BCP 47 language tags:

Tag	Language
`en`	English
`en-US`	American English
`en-GB`	British English
`es`	Spanish
`fr`	French
`de`	German
`zh`	Chinese
`zh-Hans`	Simplified Chinese
`zh-Hant`	Traditional Chinese
`ja`	Japanese
`ko`	Korean
`ar`	Arabic
`he`	Hebrew
`ru`	Russian
`pt`	Portuguese
`pt-BR`	Brazilian Portuguese

Inline Language Changes

Mark content in different languages:

<p>The French phrase <span lang="fr">c'est la vie</span> means "that's life".</p>

<blockquote lang="de">
  <p>Die Grenzen meiner Sprache bedeuten die Grenzen meiner Welt.</p>
  <footer>— Ludwig Wittgenstein</footer>
</blockquote>

The `dir` Attribute (RTL Languages)

For right-to-left languages (Arabic, Hebrew, Persian, Urdu):

<html lang="ar" dir="rtl">

For mixed content:

<p dir="rtl" lang="ar">مرحبا بالعالم</p>
<p dir="ltr" lang="en">Hello World</p>

Use dir="auto" for user-generated content:

<input type="text" dir="auto" name="comment"/>
<textarea dir="auto"></textarea>

Language Alternatives

The `hreflang` Attribute

Link to alternate language versions:

<head>
  <!-- Self-referential -->
  <link rel="alternate" hreflang="en" href="https://example.com/page"/>

  <!-- Other languages -->
  <link rel="alternate" hreflang="es" href="https://example.com/es/page"/>
  <link rel="alternate" hreflang="fr" href="https://example.com/fr/page"/>
  <link rel="alternate" hreflang="de" href="https://example.com/de/page"/>

  <!-- Default/fallback -->
  <link rel="alternate" hreflang="x-default" href="https://example.com/page"/>
</head>

Language Switcher Pattern

<nav aria-label="Language selection">
  <ul>
    <li><a href="/en/" hreflang="en" lang="en">English</a></li>
    <li><a href="/es/" hreflang="es" lang="es">Español</a></li>
    <li><a href="/fr/" hreflang="fr" lang="fr">Français</a></li>
    <li><a href="/ar/" hreflang="ar" lang="ar" dir="rtl">العربية</a></li>
  </ul>
</nav>

Character Encoding

UTF-8 (REQUIRED)

Always declare UTF-8 encoding as the first element in <head>:

<head>
  <meta charset="utf-8"/>
  <!-- Other meta tags after -->
</head>

Special Characters

Use actual Unicode characters, not HTML entities when possible:

<!-- Prefer actual characters -->
<p>Price: €50 • Copyright © 2024 • Température: 20°C</p>

<!-- Entities only when needed for markup -->
<p>&lt;tag&gt; shows a tag</p>

Translation-Friendly Markup

Avoid Concatenation

Do not build sentences from fragments:

<!-- BAD: Fragments break translation -->
<p><span>You have</span> <span class="count">5</span> <span>items</span></p>

<!-- GOOD: Complete translatable unit -->
<p>You have <data value="5">5 items</data> in your cart.</p>

Use `<data>` for Values

Separate translatable text from raw values:

<p>Price: <data value="49.99">$49.99</data></p>
<p>Status: <data value="active">Active</data></p>

Avoid Text in Images

Text in images cannot be translated:

<!-- BAD -->
<img src="welcome-banner.jpg" alt="Welcome to our site"/>

<!-- GOOD -->
<figure>
  <img src="banner-background.jpg" alt=""/>
  <figcaption>Welcome to our site</figcaption>
</figure>

Use `translate` Attribute

Mark content that should not be translated:

<!-- Brand names, code, proper nouns -->
<p>Download <span translate="no">Acme Pro</span> today.</p>
<code translate="no">npm install my-package</code>
<p>Contact: <span translate="no">support@example.com</span></p>

Date, Time, and Numbers

Semantic Time Element

Always use <time> with machine-readable datetime:

<!-- Dates -->
<time datetime="2024-12-25">December 25, 2024</time>
<time datetime="2024-12-25">25/12/2024</time>
<time datetime="2024-12-25">25 décembre 2024</time>

<!-- Times -->
<time datetime="14:30">2:30 PM</time>
<time datetime="14:30">14:30</time>
<time datetime="14:30">14h30</time>

<!-- Full datetime -->
<time datetime="2024-12-25T14:30:00Z">December 25, 2024 at 2:30 PM UTC</time>

<!-- Durations -->
<time datetime="PT2H30M">2 hours and 30 minutes</time>

Numbers and Currency

Use <data> to preserve raw values:

<!-- Currency -->
<data value="USD 99.99">$99.99</data>
<data value="EUR 99.99">99,99 €</data>
<data value="JPY 10000">¥10,000</data>

<!-- Numbers -->
<data value="1000000">1,000,000</data>
<data value="1000000">1 000 000</data>
<data value="1000000">1.000.000</data>

Pluralization

Structure for Translation Systems

Avoid English-specific plural logic:

<!-- BAD: Assumes English plural rules -->
<p>You have <span class="count">1</span> item(s)</p>

<!-- GOOD: Complete phrases for each case -->
<p data-plural-zero="You have no items"
   data-plural-one="You have 1 item"
   data-plural-other="You have {count} items">
  You have 5 items
</p>

CLDR Plural Categories

Different languages have different plural rules:

Category	English	Russian	Arabic
zero	-	-	0 items
one	1 item	1, 21, 31...	1 item
two	-	-	2 items
few	-	2-4, 22-24...	3-10 items
many	-	5-20, 25-30...	11-99 items
other	2+ items	-	100+ items

Accessibility for i18n

Language Changes for Screen Readers

Screen readers switch pronunciation based on lang:

<p>The German word <span lang="de">Weltanschauung</span> has no English equivalent.</p>

Reading Direction

Ensure logical reading order in RTL:

<article dir="rtl" lang="ar">
  <h1>عنوان المقال</h1>
  <p>نص الفقرة هنا.</p>

  <!-- LTR content within RTL -->
  <pre dir="ltr"><code>console.log("Hello");</code></pre>
</article>

Content Structure for Translation

Meaningful IDs

Use semantic IDs that survive translation:

<!-- BAD -->
<section id="section-1">
<h2 id="welcome-message">Welcome!</h2>

<!-- GOOD -->
<section id="introduction">
<h2 id="hero-heading">Welcome!</h2>

Consistent Structure

Maintain parallel structure across languages:

<!-- All language versions should have same structure -->
<article>
  <header>
    <h1><!-- Translated title --></h1>
    <p class="byline"><!-- Translated byline --></p>
  </header>
  <div class="content">
    <!-- Translated content -->
  </div>
  <footer>
    <!-- Translated footer -->
  </footer>
</article>

Meta Tags for i18n

<head>
  <meta charset="utf-8"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>

  <!-- Language/locale -->
  <meta http-equiv="content-language" content="en"/>
  <meta property="og:locale" content="en_US"/>
  <meta property="og:locale:alternate" content="es_ES"/>
  <meta property="og:locale:alternate" content="fr_FR"/>

  <!-- hreflang links -->
  <link rel="alternate" hreflang="en" href="https://example.com/"/>
  <link rel="alternate" hreflang="es" href="https://example.com/es/"/>
  <link rel="alternate" hreflang="x-default" href="https://example.com/"/>
</head>

i18n Checklist

Before finalizing internationalized content:

<html lang="..."> attribute set correctly
<meta charset="utf-8"/> is first in <head>
dir="rtl" set for RTL languages
hreflang links for all language versions
Inline lang attributes for foreign phrases
<time datetime="..."> for all dates/times
<data value="..."> for numbers and currency
translate="no" on brand names and code
No text concatenation that breaks translation
No text embedded in images
Consistent structure across language versions

Common Mistakes

Mistake	Problem	Solution
Missing `lang`	Screen readers use wrong pronunciation	Always set `<html lang="...">`
Missing `dir`	RTL text displays incorrectly	Add `dir="rtl"` for Arabic, Hebrew, etc.
Hardcoded dates	"12/25/2024" means different things	Use `<time datetime="...">`
Text in images	Cannot be translated	Use HTML text with CSS styling
Concatenation	Word order varies by language	Use complete translatable phrases
Entity overuse	Harder to read/edit	Use actual Unicode characters

Related Skills

xhtml-author - Write valid XHTML-strict HTML5 markup
javascript-author - Write vanilla JavaScript for Web Components with function...
accessibility-checker - Ensure WCAG2AA accessibility compliance
metadata - HTML metadata and head content

i18n

Install Skill

SKILL.md

Internationalization (i18n) Skill

Essential Attributes

The `lang` Attribute (REQUIRED)

Inline Language Changes

The `dir` Attribute (RTL Languages)

Language Alternatives

The `hreflang` Attribute

Language Switcher Pattern

Character Encoding

UTF-8 (REQUIRED)

Special Characters

Translation-Friendly Markup

Avoid Concatenation

Use `<data>` for Values

Avoid Text in Images

Use `translate` Attribute

Date, Time, and Numbers

Semantic Time Element

Numbers and Currency

Pluralization

Structure for Translation Systems

CLDR Plural Categories

Accessibility for i18n

Language Changes for Screen Readers

Reading Direction

Content Structure for Translation

Meaningful IDs

Consistent Structure

Meta Tags for i18n

i18n Checklist

Common Mistakes

Related Skills

Install Skill

SKILL.md

Internationalization (i18n) Skill

Essential Attributes

The lang Attribute (REQUIRED)

Inline Language Changes

The dir Attribute (RTL Languages)

Language Alternatives

The hreflang Attribute

Language Switcher Pattern

Character Encoding

UTF-8 (REQUIRED)

Special Characters

Translation-Friendly Markup

Avoid Concatenation

Use <data> for Values

Avoid Text in Images

Use translate Attribute

Date, Time, and Numbers

Semantic Time Element

Numbers and Currency

Pluralization

Structure for Translation Systems

CLDR Plural Categories

Accessibility for i18n

Language Changes for Screen Readers

Reading Direction

Content Structure for Translation

Meaningful IDs

Consistent Structure

Meta Tags for i18n

i18n Checklist

Common Mistakes

Related Skills

The `lang` Attribute (REQUIRED)

The `dir` Attribute (RTL Languages)

The `hreflang` Attribute

Use `<data>` for Values

Use `translate` Attribute