"There are four variables that need to be set on almost any modern Linux distribution to fully localize a system:
"LANG
LANGUAGE
LINGUAS
LC_ALL
"LC_ALL is actually a meta-variable that sets a whole bunch of other variables which start with LC If your goal is to have everything set for what is normal in a given language and country you needn't worry about that. Setting only one or some of these variables results in a mixed language. I've seen how-to articles saying to just set LANG, for example. If the default language is English and you set LANG to es_MX (Spanish for Mexico) the net result is a Spanglish system which probably isn't what most people want.
"Where you actually set the variables depends on two things. First, you need to decide if you want to change you system default language and locale or just make changes on a user-by user basis. Second, if you are changing for an individual user you need to know what the default shell is for that user. If you use more than one shell you may need to make the changes in more than one place."
