#Internationalization or "I18n"

##Internationalization Basics
i18n—short for "internationalization." (There are 18 letters between the "i" and the "n" in "internationalization.") Internationalization means architecting and developing an application in order to bring support for a second locale—possibly at a future time. 

The default tool for internationalizing a rails application is with the ruby i18n gem. 

Basically, the i18n gem creates a directory called config/locales. Rails then stores the application's various languages in a yaml file, such as en.yml for English or fr.yml for French.

The I18n gem ships with a feature called variable interpolation that allows you to use variables in translation definitions and pass the values for these variables to the translation method.

 Example en.yml file:

    en:
      hello_world: "Hello world"
      hello: "Hello %{name}"

Example fr.yml file:

    fr:
      hello_world: "Bonjour le monde"
      hello: "Bonjour %{name}"

Possible ERB code:

    <p>
       <%= I18n.translate("hello_world", :locale => "en") %>
    </p>
    <p>
       <%= I18n.translate("hello", :locale => "en", :name => "James") %>
    </p>
     <p>
        <%= I18n.translate("hello_world", :locale => "fr") %>
     </p>
     <p>
        <%= I18n.translate("hello", :locale => "fr", :name => "James") %>
    </p>

The output would be:

    Hello world
    Hello James
    Bonjour le monde
    Bonjour James