[CentOS] Language interfaces and X.Org sessions per user

OS: CentOS 5.0 x86.


Q1: Is it possible different users to have different language interfaces
     (menus etc) on the same machine under X.Org (GNOME or KDE)?

Q2: Is it possible to have more than one X.Org sessions running on the
     same machine, so as different users to log in at the same time, and
     switch between users X.Org sessions (one using GNOME, other using
XFCE)
     by using the usual Ctrl-Alt-Fx keys?


Thanks in advance.