private function getMetaLanguage(): string {
        $lang = '';

        $el = $this->article()->getDoc()->find('html[lang]');

        if ($el->count()) {
            $lang = $el->first()->attr('lang');
        }

        if (empty($lang)) {
            $selectors = [
                'html > head > meta[http-equiv=content-language]',
                'html > head > meta[name=lang]',
            ];

            foreach ($selectors as $selector) {
                $el = $this->article()->getDoc()->find($selector);

                if ($el->count()) {
                    $lang = $el->first()->attr('content');
                    break;
                }
            }
        }

        if (preg_match('@^[A-Za-z]{2}$@', $lang)) {
            return strtolower($lang);
        }

        return '';
    }