OK .... i'm an idiot... i just found the answer two lines below where I stopped reading on the php.net/manual page
Many thanks to Morgan Christiansson for this post
Hope that maybe this has helped someone... or at least given you a little chuckle at my expense =)
check /usr/share/locale/ if you want more info about the locale available
with your *NIX box
there is also a file called /usr/share/locale/locale.alias with a list of
aliases
such as swedish for sv_SE
Note: export LC_ALL=swedish made a lot of programs swedish for me, it's
also possible to make them russian or japanese 🙂