You poor thing... I have bad news for you: that distro is very old now. You are strongly advised to change distro to one that has community support.
If the additional languages are available on the install CD, you should be in luck. You can try the setup agent:
# rm /etc/sysconfig/firstboot
# /usr/sbin/firstboot --reconfig
... see if that lets you.
But seriously: change distro!