Following are a number of back-translations as well as a sample translation for translators of Isaiah 42:9:

• Kupsabiny: “Listen, what I said long ago have come to pass
  and I am saying new things.
  I shall show you those things before they happen.’” (Source: Kupsabiny Back Translation)
• Newari: “Look, the former matters have [already] happened,
  now I will tell you [about] new matters.
  Before it happens
  I will make you an announcement about it."” (Source: Newari Back Translation)
• Hiligaynon: “What I had-prophesied had-been-fulfilled, and now I will-reveal the new (plur.) things before these will-happen.’” (Source: Hiligaynon Back Translation)