public static function get_closest_translation($locale)
    {
        // Check if exact match
        $pool = self::getSources()->getKnownLocales();
        if (isset($pool[$locale])) {
            return $locale;
        }

        // Fallback to best locale for common language
        $localesData = static::getData();
        $lang = $localesData->langFromLocale($locale);
        $candidate = $localesData->localeFromLang($lang);
        if (isset($pool[$candidate])) {
            return $candidate;
        }
        return null;
    }