Rails Localization (i18n) - English & Arabic

Rails i18n enables multi-language support by configuring available_locales and default_locale in config/i18n, then organizing translation files under config/locales/en.yml and ar.yml. Create YAML files with key-value pairs for each language, set up a locale switcher in your layout, and use t() helpers in views to pull translated strings.

RTL support in Rails requires setting locale-specific stylesheets or CSS classes that reverse text direction and element alignment for Arabic. Configure i18n to detect the current locale, apply dir="rtl" attributes conditionally in views, and use CSS media queries or class-based styling to mirror layouts when locale is :ar.

Rails i18n handles date and number formatting through locale files using strftime patterns and number formatting rules. Define formats in config/locales/en.yml and ar.yml under i18n.time.formats and i18n.number.formats, then use I18n.l() to localize dates and numbers, which automatically applies the correct locale's formatting rules.

Arabic plurals and gender agreement are supported through Rails i18n's pluralization rules. Define complex plural rules in your locale configuration and use interpolation with count and gender variables in YAML translation keys to generate grammatically correct Arabic text based on context.

Locale switching integrates with Rails routing using locale-scoped routes defined in config/routes.rb with scope :locale. Set the locale in ApplicationController using before_action or around_action callbacks that extract locale from URL params, cookies, or headers, then use set_locale to apply it globally for that request.

Translations apply across controllers, views, models, and mailers using the same i18n infrastructure. Use t() or I18n.t() in any Rails class to access translation keys, enabling consistent localization of validation messages, email templates, and dynamic content generated outside the view layer.