install_import_locales in includes/install.core.inc
Imports languages via a batch process during installation.
install_select_locale_form in includes/install.core.inc
Form constructor for the language selection form.
locale_add_language in includes/locale.inc
API function to add a language.
locale_languages_predefined_form_submit in modules/locale/locale.admin.inc
Process the language addition form submission.
locale_languages_predefined_form_validate in modules/locale/locale.admin.inc
Validate the language addition form.
locale_translate_import_form_submit in modules/locale/locale.admin.inc
Process the locale import form submission.
_locale_prepare_predefined_list in includes/locale.inc
Prepares the language code list for a select form item with only the unsupported ones