LC_ALL & LANG are Environment Variables. While the Language and Region Control Panel Applet may effect the LANG variable, The LC_ALL variable is controlled directly in the Environment Variables tab of the System Control Panel Applet.

More background available at http://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html.

The question you have to ask yourself is 'what exactly is your script trying to do with the Locale information?' and more importantly 'where are you located?'. Then you may have some clue as to what values to which you might want to set those variables.