Following are a number of back-translations as well as a sample translation for translators of Isaiah 54:12:

• Kupsabiny: “I shall build the thing that one looks far from (tower)
  with/using beautiful things.
  And there at the gates and wall,
  I shall build with beautiful stones.” (Source: Kupsabiny Back Translation)
• Newari: “Your defense walls [will be built] with various kinds of red rubies,
  your main gate [will be built] with sparkling jewels and
  all the walls will be built for you from very precious stones.” (Source: Newari Back Translation)
• Hiligaynon: “I will-use the rubi stones to make your (sing.) tower, and I will-use the beautiful stones to make your (sing.) gates and stone-walls.” (Source: Hiligaynon Back Translation)