Turbine has a concept called modules, which is a special class loader path. Multiple module class paths can be configured by simply adding a path to the root directory of your modules. Take a look at the TurbineResources.properties.merge:
module.packages=org.apache.jetspeed.tutorial.modules
Modules is made up of different kinds of modules: actions, layouts, screens, navigations, pages, and localisations. Jetspeed uses the module path to find the resource bundles in the localisation modules.
Resource bundles and the default language are also specified in TurbineResources.properties.merge. Notice that the tutorial's resource bundle is listed first, overriding the Jetspeed resource bundle.
locale.default.bundles = org.apache.jetspeed.tutorial.modules.localization.JPortalLocalization,
org.apache.jetspeed.modules.localization.JetspeedLocalization
locale.default.language=en
locale.default.country=US