Language settings sier:
Default language lang English (en)
Choose a default language for the whole site. Users can override this setting later.
Languages on language menu langlist
Leave this blank to allow users to choose from any language you have in this installation of Moodle. However, you can shorten the language menu by entering a comma-separated list of language codes that you want. For example: en,es_es,fr,it
Cache language menu langcache
Cache the language menu. Saves a lot of memory and processing power. If you enable this, the menu takes a few minutes to update after you have added or removed languages.
Sitewide locale locale
Choose a sitewide locale - this will override the format and language of dates for all language packs (though names of days in calendar are not affected). You need to have this locale data installed on your operating system (eg for linux en_US.UTF-8 or es_ES.UTF-8). In most cases this field should be left blank.