Following are a number of back-translations as well as a sample translation for translators of Isaiah 57:6:

• Kupsabiny: “You bring the small round stones of the valley
  and go to worship (them).
  You make sacrifices that are poured out to those things
  and give them food as a reward.
  I will punish you for these deeds/matters.” (Source: Kupsabiny Back Translation)
• Newari: “The idols of rock that are the smooth stones which stay in the gorge are your portion.
  For them you have offered drink offerings and grain offerings.
  even though I know all this, should I accept it?” (Source: Newari Back Translation)
• Hiligaynon: “The shining/smooth stones in the places-where- water -flows are your (plur.) little-gods. You (plur.) worship these by sacrificing drink offerings and gift offerings. Will I be happy by your (plur.) doing this?” (Source: Hiligaynon Back Translation)