I am developing a survey that will use multiple languages. What words shall I use for the bottom of a Google survey form for "Back" and "Next"?
While 'Zurück' and 'Weiter' are perfectly fine, consider 'Vorige Frage' and 'Nächste Frage' (previous/next question) given the context of a survey. Especially when addressing the general public, computer literacy will vary greatly among a good sample population so being precise can be helpful in meeting expectations.
Example: Consider questions spanning multiple screens: 'back/next' can be construed as referring to the previous/next question or the previous/next page of the current question.
While this may appear far-fetched, pampering your subjects is somewhat best practice (an important rationale is preventing early aborts).