In Devarim 27:8, the Torah says to "write all the words of the Torah explained well" (- "Ba'aer Hetev".
Rash"i, citing Sotah 35b, says that this was translated into 70 languages. Sifsei Chachamim elaborates that this was done so that the nations of the world could make copies. Also, see Why translate Torah to 70 languages
When Joshua and the Jews crossed the Jordan River and camped in Gilgal, they wrote the Torah on stones, as Moshe had commanded them in Devarim.
Did they translate the Torah at that time? Was it done by one person or several people? Who knew all 70 languages? How did they get all 70 language translations of the whole Torah on 12 stones?