static function setDefaultLanguage(string $language) {
        if(!\class_exists($language, true)) {
            throw new \InvalidArgumentException('Unknown language class');
        } elseif(!\in_array(\CharlotteDunois\Validation\LanguageInterface::class, \class_implements($language), true)) {
            throw new \InvalidArgumentException('Invalid language class (not implementing language interface)');
        }
        
        static::$defaultLanguage = $language;
    }