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

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.