Make API Management Portal site multi-languages

I'm trying to make my site multi languages. Because of the fact that API managemenet portal site is using paperbits, I thought it is possible to do that.
I found below code in config.design.json file in api managemenet portal site repo.

{
    "environment": "development",
    "managementApiUrl": "https://xxxxxxx.management.azure-api.net",
    "managementApiAccessToken": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
    "backendUrl": "https://xxxxxxxxxxx.developer.azure-api.net",
    "useHipCaptcha": false,
}

In config.design.json file of paperbits demo app, it looks like below.

{
    "firebase": {
        "apiKey": "< your API key >",
        "authDomain": "< your domain >.firebaseapp.com",
        "databaseURL": "https://< your database URL >.firebaseio.com",
        "projectId": "< your project ID >",
        "storageBucket": "< your storage bucket >.appspot.com",
        "databaseRootKey": "/",
        "storageBasePath": "/",
        "auth": {
            "basic": {
                "email": "< user email >",
                "password": "< user password >"
            }  
        }
    },
    "features": {
        "seo": true,
        "localization": true,
        "preview": true
    },
    "environment": "design"
}

I found that localization feature exists only in paperbits.

"features": {
        "seo": true,
        "localization": true,
        "preview": true
}

So, I add above code on api managemenet portal config.design.json file as well.

Finally, I could modify site on GUI with multi locals and languages. However, once I change the text on one-language site, another language version of it changes automatically.

Plus after publishing it, I could not see any changes on dist file and could not find any page for another language which I added.
Could anyone help?