Following are a number of back-translations as well as a sample translation for translators of Isaiah 59:12:

• Kupsabiny: “We have sinned much, oh, God,
  and our sins accuse us.
  Truly, we have done mistakes
  and we know our sins.” (Source: Kupsabiny Back Translation)
• Newari: “For our transgressions before you are many,
  and our sins give witness against us.
  Our transgressions are with us
  and we confess our sins.” (Source: Newari Back Translation)
• Hiligaynon: “For our (incl.) sins are now many before/[lit. in front of] God, and this proves that we (incl.) should be-punished. Yes, we (incl.) know that we (incl.) always sin.” (Source: Hiligaynon Back Translation)