Send notification messages in the target user's language.

config/initializers/action_mailer.rb

@@ -14,3 +14,25 @@ module Net
     end
   end
 end
+
+# Monkey patch to allow sending of messages in specific locales
+module ActionMailer
+  class Base
+    adv_attr_accessor :locale
+  private
+    alias_method :old_render_message, :render_message
+
+    def render_message(method_name, body)
+      old_locale= I18n.locale
+
+      begin
+        I18n.locale = @locale
+        message = old_render_message(method_name, body)
+      ensure
+        I18n.locale = old_locale
+      end
+
+      message
+    end
+  end
+end