There are many different languages available for a Drupal installation, but what if you want to have a site with more than one language? Drupal is up to the task, but it's not a trivial procedure. There are two areas that need translation.
First, you'll need to translate the interface, which includes the button texts, drop down menus, messages and other languages you use to interact with the site. Customizing the interface is fairly simple, and there are language files you can download that will help you make short work of it. Drupal developers often refer to this as localization.
Second, you'll need to translate the content. There are some modules that will make this possible, but this does require more effort than translating the interface.
Read more ...