Hi,
DISQUS identifies each discussion based on the page URL. Since the URL in the two pages is different it considers two different discussions.
Actually what you need can be done using the disqus identifier variable
help.disqus.com/customer/portal/articles/472098-javascript-configuration-variables#disqus_identifier . You will need to have a common identifier for the pages you want to have the same comments.
This is a customization and is not supported by the plugin. Also it makes no sense to add it since in most cases translations are considered different pages.