Although in http://www.gentoo.org/doc/de/guide-localization.xml says that one should use /etc/profile to set the LANG variable, there was a consensus in the thread http://forums.gentoo.org/viewtopic.php?p=475460 that /etc/env.d/02locale or 02language or whatever is a better place to set the LANG variable. Reproducible: Always Steps to Reproduce:
LANG is user specific, file a bug to fix that doc.