Following are a number of back-translations as well as a sample translation for translators of Isaiah 59:20:

• Kupsabiny: “The Redeemer says that (he) will come to Zion and save people,
  he shall save the descendants of Jacob who repent.” (Source: Kupsabiny Back Translation)
• Newari: “Redeemer will come to Zion to the descendants of Jacob
  who have repented of their sin.
  The LORD Almighty has declared [it].” (Source: Newari Back Translation)
• Hiligaynon: “The LORD said, ‘The one-who-will-save you (plur.) who are the descendants of Jacob will-arrive in Zion and he will-save the one-who-repents from his sins.” (Source: Hiligaynon Back Translation)