Following are a number of back-translations as well as a sample translation for translators of Isaiah 42:20:

• Kupsabiny: “You have seen many things and you have not understood/realized (it).
  You are listening (cut the ears) and you hear nothing.’” (Source: Kupsabiny Back Translation)
• Newari: “You have seen many things,
  but [you] have paid no attention.
  Your ears have been open,
  but you have not even heard anything."” (Source: Newari Back Translation)
• Hiligaynon: “You (plur.) now have-seen- many -things but you (plur.) have- not -paid-any-attention to it. You (plur.) could-have-heard but you (plur.) do- not -listen.’” (Source: Hiligaynon Back Translation)