I don’t think that will be easy to translate to all languages. What about languages that have multiple plurals?
What about "There are 1 unread topic and 1 new topic remaining,”?
The German translation uses something similar: “1 unread topic and 1 new topic remaining.”
Crowdin is quite helpful for testing these strings because can can choose parameters and see a preview of the text. For example
You can find the text here: Crowdin
