Add a language from the survey's General settings, then translate as much or as little as you like — anything left untranslated automatically falls back to the default language, so a partially translated survey never shows blank text.
With a language selected, the Designer tab lets you edit titles, descriptions, choices and validation messages directly on the canvas, in place, with an immediate preview of how the translated text will lay out. This is the quickest route for a short survey or a handful of languages.
For longer surveys or larger translation jobs, the Translation tab lists every translatable string across the whole survey in a spreadsheet-style grid — one column per language. Export to CSV to send the file to a translator, then import their completed version back in. Each question's language automatically follows the visitor's Umbraco culture on the published site.