The Survey app allows you to add translations so that whoever receives a survey, it gets it delivered in their language.
In order to create a translation in the app click on the translations tab at the top of the screen.
If you already have other languages in Zendesk switched on, you will see them listed on the left-hand side. As you can see in this image, the only other language currently turned on is Dutch.
If you're needing more languages, you will simply need to turn them on in Zendesk. Here is a link to an article on how to set languages up in Zendesk.
To add a newly translated version of the text used in surveys simply click on the language on the left and type in what you want it to say.
Once you've added all your translations, in line with Zendesk's native language functionality, any person who receives a survey will now see it in the language their ticket is already in.