There are a number of considerations for deploying CAS in a locale other than en-US, some of which are discussed here.
New CAS documentation site
CAS documentation has moved over to jasig.github.io/cas, starting with CAS version 4.x. The wiki will no longer be maintained. For the most recent version of the documentation, please refer to the aforementioned link.
The Localization page describes how to switch from the default en-US locale to any of a number of supported locales, as well as instructions for adding support for a locale not provided out of the box.
Supporting character sets other than ASCII will be a primary concern for many international deployments. The following steps are required to support end-to-end UTF-8 character set encoding in CAS.