I installed LibO portable v.3.4.1 multilanguage with all languages, set the UserInterface, LocalSettings, DefaultLanguage to german language (Tools> Options> LanguageSettings> Languages>) "changes take effekt after restart" after restart, language settings for DefaultLanguage and LocaleSettings were still set german, UserInterface language was changed back to english (USA).
so I copied my LibO v3.4.1 (nonportable)settings, which works fine with german userInterface language to my portable LibO installation.
(copied the whole content from c:\Documents and Settings\....\...\user\ xxx to ...\LibreOfficePortableTest\Data\settings\user\ xxx)
after a start of LibO portable, UserInterface language was still english (USA)!
so I copied back my settings (whole content from ...\LibreOfficePortableTest\Data\settings\user\ xxx to c:\Documents and Settings\....\...\user\ xxx )
after restarting my nonportable LibO, the UserInterface language there was also set to english. but on my nonportable LibO I can set the language I want and it will appear after restart.
It seems, my portable version resets the UserInterface language configuraton while restarting(starting)always to english. Even a known working configuration.
I'm unable to set UserInterface language to any other than english!