i18n

## What I do - Prepare software for multiple languages - Handle text expansion and contraction - Manage date, time, and number formats - Support right-to-left (RTL) languages - Implement locale-specific content - Structure translation workflows ## When to use me When building applications that need to support multiple languages, regions, or cultural preferences. ## Key Concepts ### i18n vs l10n ``` i18n: Internationalization - code preparation l10n: Localization - language/region adaptation ``` ### Implementation Patterns ```javascript // Translation keys t('greeting', { name: 'John' }) // en.json: "Hello, {name}!" // es.json: "¡Hola, {name}!" // Pluralization t('items', { count: n, plural: true }) // en: 1 item, 5 items // ru: 1 предмет, 5 предметов ``` ### Common Libraries ```python # Python from babel import Locale from django.utils import translation # JavaScript import i18next from 'i18next'; import { IntlMessageFormat } from 'intl-messageformat'; # Java import java.text.MessageFormat; import java.util.Locale; ``` ### RTL Support ```css [dir="rtl"] { direction: rtl; text-align: right; } /* Swap left/right specific styles */ .sidebar { margin-left: 1rem; } [dir="rtl"] .sidebar { margin-right: 1rem; } ``` ### Formatting by Locale ``` Dates: en-US: 1/15/2026, en-GB: 15/01/2026 Numbers: en: 1,234.56, de: 1.234,56 Currency: $1,234.56, €1.234,56 ``` ### Best Practices 1. Externalize all strings 2. Use ICU message format 3. Test with pseudo-locales 4. Plan for text expansion (+30%) 5. Separate locale from logic 6. Use language codes (ISO 639-1)