Following are a number of back-translations as well as a sample translation for translators of Isaiah 41:20:

• Kupsabiny: “Then people shall hear and understand/realize
  that it is the God of Israel who has done these things.’” (Source: Kupsabiny Back Translation)
• Newari: “For people seeing [this] may understand
  and may think about it [lit.: may consider].
  They will certainly understand that this is the work of the LORD’s hand.
  [That] this has been created by the holy God of Israel.” (Source: Newari Back Translation)
• Hiligaynon: “so-that the people will-see, will-know, and will-understand that I, the LORD, the holy God of Israel, is the one-who-did this.” (Source: Hiligaynon Back Translation)