The quiz data is stored as a custom post type, so you’ll be able to create different versions of the quiz associated with different languages using the most popular multi-language plugins like Polylang and WPML. However this is not entirely necessary, since all text that displays in the quiz is controlled from within the quiz options. So you don’t necessarily need to make the Quiz post type translatable, since each version of the quiz will have a different shortcode and you can use that shortcode on pages or posts that belong to a specific language.
When creating a quiz on a specific language you should just write the questions and answers on that language. What you’ll also need to do is change the quiz text labels to reflect the language.
All text that the quiz displays can be modified here. These are unique to each quiz you create, so you can edit them freely without affecting other quizzes, allowing you to display messages on different languages and with vocabulary that relates with the quiz topic.