To setup interactive translation
Enable Multilingual and Use database for translation on the i18n/Multilingual control panel ( tiki-admin.php?page=i18n )
Give the permission tiki_p_edit_languages to the group that should be allowed to edit languages. If you skip this step, only admins will be able to. Please note that if you give tiki_p_edit_languages to regular (non-admin users), they'll only be able to translate non-admin interfaces.