Well, if you want to keep US locale, but include utf-8 support do next:
-edit as root /etc/profile.d/lang.sh with your favourite editor
-comment this line with # sign
-uncomment this line (a little below):
That should solve problem for you.
Else, you can set up locale for your language. Just type locale -a
command, find line that suites your language and put it in edited file by replacing current setting. In example, for my language (Serbian) I would replace export LANG=en_US.UTF-8
with export LANG=sr_CS.utf8