So, this is a static site. If we want comments, we should store comments data in our repository, or we can use third-party services.
I do not want to use third-party services yet. I came across staticman, which seems can solve my problem. But there was a problem during installation. The official public instance does not work.
It took some time to figure out how to raise and deploy it. Fortunately, this is not difficult.
I just need to add a form for adding a comment, though. The next time I will implement internationalization in a naive way.