public static function extractLocalizedStrings(\DOMElement $parent, string $namespaceURI, string $localName) : array
    {
        $ret = [];
        foreach ($parent->childNodes as $node) {
            if ($node->namespaceURI !== $namespaceURI || $node->localName !== $localName) {
                continue;
            } else if (!($node instanceof DOMElement)) {
                continue;
            }

            if ($node->hasAttribute('xml:lang')) {
                $language = $node->getAttribute('xml:lang');
            } else {
                $language = 'en';
            }
            $ret[$language] = trim($node->textContent);
        }

        return $ret;
    }