// Set the default locale for a multi-lingual site
Translatable::set_default_locale('en_GB');

// Define which objects you wish to include in your translations (can be any DataObject)
SiteTree::add_extension('Translatable');
SiteConfig::add_extension('Translatable');
SomeOtherPage::add_extension('Translatable');

// Set the number of language you wish to have available
Translatable::set_allowed_locales(array(
    'pt_BR',
    'en_GB',
    'fr_FR',
    'pt_PT',
    'es_ES'
));