From the module page: "A small distribution to install Drupal with user interface translations pulled automatically from localize.drupal.org. It is suggested you use this distribution to start off with Drupal if you'd like to set up a localized site."
"While scientists study how nature works, engineers create new things, such as products, websites, environments, and experiences. Because engineers and scientists have different objectives..."
Here are some examples of using Drupal's states API. It shows the use of OR and XOR (which only work with jQuery 1.8 or above, apparently). More examples can be found in the examples project in the form example module.