The strategy has been reworked a bit to make it more reliable.
Linuxconf was not supporting this properly in the user account dialog.
config something something else another thing
The original way was not duplicating the first "config" and this created a menu sometime difficult to read (the verb was missing).
You will find the language package at ftp://ftp.solucorp.qc.ca/pub/linuxconf/devel/lang . Use the HTML form at http://www.solucorp.qc.ca/linuxconf/download.hc . This form will help you select the proper packages.
Not that the LANG package are platform independent. I have not found a way to produce "noarch" package out of the same source RPM (unless all sub-package are of type "noarch"). This binary compatibility explain why you won't find LANG package along with the core package in the distribution directory.
Hope it will save you some download time and some disk space.