Following are a number of back-translations as well as a sample translation for translators of Isaiah 41:21:

• Kupsabiny: “God is saying
  the one who is the king of Israel,
  ‘Go and arrange your words.
  Show what you are able to do!” (Source: Kupsabiny Back Translation)
• Newari: “The LORD, Jacob’s king says,
  "Bring your cases to me.
  Bring your arguments to me.” (Source: Newari Back Translation)
• Hiligaynon: “The LORD, the King of Israel, said to the little-gods, ‘Okay, you (plur.) complain and reason-out!” (Source: Hiligaynon Back Translation)