install_select_locale_form in ./install.php
Form API array definition for language selection.
locale_add_language in includes/
API function to add a language.
locale_languages_predefined_form_validate in includes/
Validate the language addition form.
locale_translate_import_form_submit in includes/
Process the locale import form submission.
_locale_prepare_predefined_list in includes/
Prepares the language code list for a select form item with only the unsupported ones