CComponentUtil::__IncludeLang

static function __IncludeLang($filePath, $fileName, $lang = false)
{
	if ($lang === false)
		$lang = LANGUAGE_ID;

	if ($lang != "en" && $lang != "ru")
	{
		$subst_lang = LangSubst($lang);
		$fname = $_SERVER["DOCUMENT_ROOT"].$filePath."/lang/".$subst_lang."/".$fileName;
		$fname = BitrixMainLocalizationTranslation::convertLangPath($fname, $subst_lang);
		if (file_exists($fname))
		{
			__IncludeLang($fname, false, true);
		}
	}

	$fname = $_SERVER["DOCUMENT_ROOT"].$filePath."/lang/".$lang."/".$fileName;
	$fname = BitrixMainLocalizationTranslation::convertLangPath($fname, $lang);
	if (file_exists($fname))
	{
		__IncludeLang($fname, false, true);
	}
}