Microsoft does only allow to change the system language of Windows for Windows 7 Enterprise and Ultimate via the GUI. If you would like to change the language in Windows 7 Home and Professional you need to do that manually
Change default log language for Websphere application server
If you are running a Websphere application server (e.g. Lotus Sametime 8.5 or Lotus Connections servers) on a Windows server with regional settings set to a non-English language you end up with log files written in that language. This is