Method parseLanguageFiles

/**
 * Searches for language directories within a certain base dir.
 *
 * @param   string  $dir  directory of files.
 *
 * @return  array  Array holding the found languages as filename => real name pairs.
 *
 * @since   3.7.0
 */
public static function parseLanguageFiles($dir = null)
{
    $languages = array();
    // Search main language directory for subdirectories
    foreach (glob($dir . '/*', GLOB_NOSORT | GLOB_ONLYDIR) as $directory) {
        // But only directories with lang code format
        if (preg_match('#/[a-z]{2,3}-[A-Z]{2}$#', $directory)) {
            $dirPathParts = pathinfo($directory);
            $file = $directory . '/langmetadata.xml';
            if (!is_file($file)) {
                $file = $directory . '/' . $dirPathParts['filename'] . '.xml';
            }
            if (!is_file($file)) {
                continue;
            }
            try {
                // Get installed language metadata from xml file and merge it with lang array
                if ($metadata = self::parseXMLLanguageFile($file)) {
                    $languages = array_replace($languages, array($dirPathParts['filename'] => $metadata));
                }
            } catch (\RuntimeException $e) {
                // Ignore it
            }
        }
    }
    return $languages;
}