```ruby
class ActionController::Base
  def set_gettext_locale
    requested_locale = params[:locale] || session[:locale] || cookies[:locale] ||  request.env['HTTP_ACCEPT_LANGUAGE']
    locale = FastGettext.set_locale(requested_locale)
    session[:locale] = locale
    I18n.locale = locale # some weird overwriting in action-controller makes this necessary ... see I18nProxy
  end
end
```

Use I18n.default_locale if no other locale found
user
```ruby
class ActionController::Base
  def set_gettext_locale
    requested_locale = params[:locale] || session[:locale] || cookies[:locale] ||  request.env['HTTP_ACCEPT_LANGUAGE'] || I18n.default_locale
    locale = FastGettext.set_locale(requested_locale)
    session[:locale] = locale
    I18n.locale = locale # some weird overwriting in action-controller makes this necessary ... see I18nProxy
  end
end
```
assistant