private static function _prepareLocale($locale, $strict = false)
    {
        if ($locale instanceof Zend_Locale) {
            $locale = $locale->toString();
        }

        if (is_array($locale)) {
            return '';
        }

        if (empty(self::$_auto) === true) {
            self::$_browser     = self::getBrowser();
            self::$_environment = self::getEnvironment();
            self::$_breakChain  = true;
            self::$_auto        = self::getBrowser() + self::getEnvironment() + self::getDefault();
        }

        if (!$strict) {
            if ($locale === 'browser') {
                $locale = self::$_browser;
            }

            if ($locale === 'environment') {
                $locale = self::$_environment;
            }

            if ($locale === 'default') {
                $locale = self::$_default;
            }

            if (($locale === 'auto') or ($locale === null)) {
                $locale = self::$_auto;
            }

            if (is_array($locale) === true) {
                $locale = key($locale);
            }
        }

        // This can only happen when someone extends Zend_Locale and erases the default
        if ($locale === null) {

            throw new Zend_Locale_Exception('Autodetection of Locale has been failed!');
        }

        if (strpos($locale, '-') !== false) {
            $locale = strtr($locale, '-', '_');
        }

        $parts = explode('_', $locale);
        if (!isset(self::$_localeData[$parts[0]])) {
            if ((count($parts) == 1) && array_key_exists($parts[0], self::$_territoryData)) {
                return self::$_territoryData[$parts[0]];
            }

            return '';
        }

        foreach($parts as $key => $value) {
            if ((strlen($value) < 2) || (strlen($value) > 3)) {
                unset($parts[$key]);
            }
        }

        $locale = implode('_', $parts);
        return (string) $locale;
    }