Following are a number of back-translations as well as a sample translation for translators of Jeremiah 51:12:

• Kupsabiny: “Raise (plur.) the banner/flag for you to fight Babylon.
  Add young men who are guarding to become many.
  Prepare those who look out to guard (watchmen)
  you there on the wall be ready to attack.’
  Those words/events that God said that he would send to Babylon have come true.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “Lift up the banner as a sign to attack Babilonia. [You (plur.)] add more guards and station now to their posts the watchers. [You (plur.)] besiege the city! It is now time that the LORD will-do what he has-planned against the people of Babilonia.’” (Source: Hiligaynon Back Translation)
• English: “Lift up a battle flag close to the walls of Babylon!
  Reinforce the/Appoint more guards,
  and tell the watchmen to stand in their positions!
  Prepare an ambush,
  because Yahweh is about to accomplish all that he has planned to do to the people of Babylon.” (Source: Translation for Translators)