public function insertLanguageItems($languageItems)
    {
        $data = [];
        foreach ($languageItems as $category => $messages) {
            foreach (array_keys($messages) as $message) {
                $data[] = [
                    $category,
                    $message,
                ];
            }
        }

        $count = count($data);
        for ($i = 0; $i < $count; $i += self::INSERT_LANGUAGE_ITEMS_LIMIT) {
            static::getDb()
                ->createCommand()
                ->batchInsert(static::tableName(), ['category', 'message'], array_slice($data, $i, self::INSERT_LANGUAGE_ITEMS_LIMIT))
                ->execute();
        }

        return $count;
    }