Following are a number of back-translations as well as a sample translation for translators of Joel 3:13:

• Kupsabiny: “Prepare the sickles
  because the crop is ready/ripe.
  Go and squeeze the grapes
  because the places for squeezing are full.
  The wine will flow from where (it is/they are) squeezed.
  The sins of those people are not few.’” (Source: Kupsabiny Back Translation)
• Newari: “Swing the Sickle because the wheat harvest time has come.
  Come, trample the grapes because the winepress is full
  and the wine containers are overflowing.
  Their wickedness has become very great.’” (Source: Newari Back Translation)
• Hiligaynon: “They seem like/as-if what is-to-be-harvested which should already be-reaped for (it is) already ripe, or seems-like a grape that should already be-squeezed/pressed because the place-for-pressing/squeezing (is) now full of grapes. They (are) now very wicked; their sins seem-like juice of grapes that overflows from its container.’” (Source: Hiligaynon Back Translation)
• Kankanaey: “Extreme is their badness, therefore they will be harvested-with-a-sickle like rice at harvest-time and they will be squeezed-out like grapes in the place-of-squeezing until it is full.’” (Source: Kankanaey Back Translation)
• English: “They are like crops that are ready to be harvested;
  so strike them like a farmer swings his sickle to cut the grain.
  They are like grapes that are piled high in the pits where they will be pressed;
  because they are very wicked,
  punish them severely now,
  like a farmer tramples on the grapes until the pits are full of juice.” (Source: Translation for Translators)