Following are a number of back-translations as well as a sample translation for translators of Isaiah 18:5:

• Kupsabiny: “God will cut down the people of Cush
  before (they) prepare/ready their soldiers.
  They shall be cut down before their preparations are fulfilled/finished
  like food that is moved (from the fire) before it is ready.” (Source: Kupsabiny Back Translation)
• Newari: “For before the crops are harvested, when the blossom becomes flower,
  Then the flower will fall and grapes grow and ripen.
  At that time he will prune that branch with a reaping hook.
  Then [he] will also cut off the spreading branches.” (Source: Newari Back Translation)
• Hiligaynon: “[Note: Hiligaynon may need to be revise for this verse.] When is not harvest-season yet, at the time still of the flowering of grapes and gradual ripening of its fruits, God will-cut-down its branches.” (Source: Hiligaynon Back Translation)