public function findSystemLanguages()
    {
        $languages = [0];

        $queryBuilder = $this->getQueryBuilder();
        $queryBuilder->getRestrictions()->add(GeneralUtility::makeInstance(HiddenRestriction::class));
        $languageRecords = $queryBuilder->select('uid')
            ->from($this->table)
            ->execute()->fetchAll();

        if ($languageRecords == false) {
            return $languages;
        }

        foreach ($languageRecords as $languageRecord) {
            $languages[] = $languageRecord['uid'];
        }
        return $languages;
    }