To set your current shell to a different language you use the bash variable LANG followed by the language you want:
LANG=en_us_8859_1
If you want to set that so its used every time add an export line to your .bashrc for that user. The .bashrc file can be found in each user's homedir, if they don't have one you can create it:
export LANG=en_us_8859_1
The command locale will show you information about locale on the server. The command locale -a will give you a list of all the locale you can use.