To localize address book, the xml file that needs to be modified is the dictionary- <lang>.xml file that is located under <uwcinstalldir>/WEB-INF/ui/html/abs directory.
You can customize the Address Book UI either for a specific locale and not under a specific domain and also for a locale under a specific domain.
Create a directory with the locale name(e.g., ja under <uwcinstall>/WEB-INF/ui/html/abs
Copy all files from <uwc-deploy>/WEB-INF/ui/html/abs to <uwc-deploy>/WEB-INF/ui/html/abs/<locale>
Make the required changes in XSL files as explained in the previous sections.