Workaround:
After the locale is changed back to English, delete the following files in the "C:\Documents and Settings\\Application Data\Cisco\Communicator" directory:
AudioTuningWizardStrings.xml
AutoUpdateStrings.xml
SFBStrings.xml
ErrorReportStrings.xml
Reload IP Communicator and the splash screen, audio tuning wizard, and preferences are in English again.
Bug ID CSCsd83023