Following are a number of back-translations as well as a sample translation for translators of Isaiah 65:20:

• Kupsabiny: “Never shall there be there an infant
  who only lives for a few days.
  No old man shall die early there
  instead of growing old in his life.
  When a person dies having hundred years
  he has died like a person who is still young.
  But the one who dies before hundred years
  is a person who is cursed.” (Source: Kupsabiny Back Translation)
• Newari: “There will never be an infant that lives [only] for some days
  or an old man who does not get to live out his full years.
  One who dies having lived [only] 100 years will be thought [to have died] young.
  And one who has not lived 100 years will be thought accursed. ” (Source: Newari Back Translation)
• Hiligaynon: “There will-be- no -more infant or young-one will-die there. The one-who-dies whose age is 100 years will-be-considered as still young, and the one-who-dies not reaching 100 (years-of-age) will-be-considered whom I punished.” (Source: Hiligaynon Back Translation)