FEMAP's GUI localization is accomplished by the presence of a .DLL with the localized language information in it. If that .DLL is not present, FEMAP will be in English. The Japanese install also installs a Japanese help system. It's easy to go back to an English GUI, delete FERES1120.dll from the main FEMAP directory. However to get back to an English help system, it's best to uninstall FEMAP, delete any leftover files, and re-install and choose English as the language.