Not available yet. The translation tools are built (lane forms-l01, row F-L01, on qa) but the Languages tab is not mounted in the editor and the visitor language switcher is not on the live form yet. Nothing below can be used today.
Who translates my form?
A machine translation drafts each language you enable, using Sarvam, an India-based provider. Every line is editable; an edit marks that line as written by you and unreviewed until you review it. Changing any text in a block translates that whole block again.
Is a machine translation of my consent text safe to publish?
Publishing warns you when legal wording such as the consent text has not been reviewed by a person in an enabled language.
What does a visitor see if a line is not translated?
Your original line, flagged as a fallback.
How is the visitor's language picked?
From the link, then the browser language, then your default. Only languages you enabled can be chosen.