OTM provides German messages and tool tips if Windows is set to use German local.
To force OTM to use German localization, edit the file OtmControlLibrary.dll.config (located in the DigaSystem directory), replace the line
<Culture>de</Culture>, and save the file back to its original directory, then restart the application that uses OTM. To force OTM to use English localization, use
This setting applies to all users of the OTM installation on the respective workstation.