Following are a number of back-translations as well as a sample translation for translators of Joel 2:20:

• Kupsabiny: “I will remove those enemies of yours in the North
  and chase them to go into the desert.
  I shall throw into the Lake of Salt
  those soldiers who are in front,
  and those who are behind
  I shall throw them into the Mediterranean with a splash.
  They shall rot and become very bad smelling.’
  God has done an amazing thing for you (plur.).” (Source: Kupsabiny Back Translation)
• Newari: “‘I will remove the army from the north
  far away from you.
  And I will drive them out to barren and deserted land.
  Those in front will be driven into the Dead Sea in the east,
  those in back westward into the Mediterranean Sea. They will die there and produce a great stench."
  Surely the LORD has done great things.” (Source: Newari Back Translation)
• Hiligaynon: “I will-cause- yours (plur.) attackers who came-from the north -to-go-away, and I will-drive them into the desert. Their first large-group/throng I will-drive into the Dead Sea and their last large-group/throng I will-drive into the Sea of Mediteraneo. Their corpses/dead-bodies will-stink.’
  (It is) truly amazing what the LORD has-done.” (Source: Hiligaynon Back Translation)
• English: “Another army of locusts will come from the north to attack you,
  but I will force them to continue past Jerusalem
  into the desert.
  Some will go into the Dead Sea in the east
  and some will go into the Mediterranean Sea in the west.
  There they will all die, and their bodies will stink.’
  Yahweh does great things!” (Source: Translation for Translators)