@JCWEB , it’s using the Javascript Fetch API when the page loads to gather the JSON data for populating the text context dynamically with the appropriate text from the JSON based upon the data-attribute which was assigned. Using this JSON approach allows for customization concerning oversight regarding translation quality as sometimes that can be a problem.
@kuligaposten also showed a more automized approach found here, using Google Translate.
https://forum.bootstrapstudio.io/t/how-to-do-multi-language-sites/3146/16