Yesterday i was on a customer site and all Portal Servers are installed on Windows Servers. The language settings are set using policies and the logs are in Brazilian Portuguese. Too bad for troubleshooting.
So i change the language to English using the following:
Append the following to the existing value for the property “Generic JVM arguments”: -Duser.language=xx -Duser.region=YY
where xx and YY values are dependent upon the desired language.
For English US the values are bellow
-Duser.language=en -Duser.region=US