I know the common
sudo languagesetup to set the system language. Does someone know how to get the system language or the language that was selected when Mac OS X was installed?
The left part of
osascript -e 'user locale of (get system info)' is the language selected in Setup Assistant (I think).
The language at the top of the list in the Language & Text preferences should be the second line of
defaults read -g AppleLanguages.