How to manage languages in Joomla
• Providing alternative language translations for the default Joomla text helps members of a multilingual community to find their way around more easily.
• Language packs are installed just like any other extension in Joomla. There are dozens of translations for Joomla on the Joomla extension site in Languages/Translations for Joomla category.
• Most language packs are available as two separate extensions (one for site and other for administrator backend). You can choose either of them or both.
• Click on Extensions -: Language manager.
• You can set default language for site and administrator backend. For making any language for site as default, select it from radio button, scroll right and click on default button at the top.
• For setting the default language for administrator, go to the respective tab. The process is same as that for site options.