information on how to translate the component for joomla
CiviCRM has its own setting to set default language. To configure CiviCRM to use an translation:


Download the translations distribution -
civicrm--l10n.tar.gz - from the CiviCRM downloads page. This
tarball contains all files for the latest available translations.
Uncompress the tarball and you will see a directory called civicrm,
containing two subdirectories called l10n and sql. The l10n directory
contains a set of sub-directories named using their local codes.
(Example: the Italian translation files will located in
/civicrm/l10n/it_IT).
Copy this l10n directory, together with all its subdirectories into
your CiviCRM codebase root directory.(note if creating the l10n
folder manually it should be ell-ten-n, not capital-I-ten-n)

For Joomla this would be site_root/administrator/components/com_civicrm/civicrm. So if you wanted the it_IT language it would look like this site_root/administrator/components/com_civicrm/civicrm/l10n/it_IT/



To enable the default language


Login to CiviCRM (as a user with "administer CiviCRM permissions").
Go to Administer » Localization » Languages, Currency, Locations.
You should now be able to see and select all the localization options
in the Default Language and drop-down menu. If you don't, and instead
can just see the default 'English (United States)' option, check the
preceding steps as the drop-down options are set by the directories
under your l10n directory. Also be sure to confirm that the l10n
directory is correctly named as l10n (that is: el-ten-en and not
eye-ten-en).


HTH

Pradeep