public function getLanguages()
    {
        if (!empty($this->languages)) {
            return $this->languages;
        }

        $this->languages = array_map(
            function ($record) {
                return $record['_id'];
            },
            $this->languageCollection->find([], ['_id' => 1])->toArray()
        );

        asort($this->languages);

        $this->languages = array_values($this->languages);

        return $this->languages;
    }