http://blogs.msdn.com/b/sharepoint__cloud/archive/2012/03/03/how-to-make-sure-office-365-users-get-mop-in-their-preferred-language.aspxNOTE : This Article is only useful if you are using Directory Synchonization to sync. users from your local AD to cloud. When user access Microsoft Online Portal it is displayed in English (unless they have made changes in their IE options). en-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)