I don’t think this feature will be prioritised until early next year.
This is not a UI change, it will be quite an in-depth change to language preferences within logged-in user user profiles, and anons separately. Moving from one language to multiple language support properly is not going to be a quick change.
The “show original” button should be global per device. When your user makes the comment, it would be appreciated if they could record a video / multiple screenshots.