Following are a number of back-translations as well as a sample translation for translators of Psalm 137:7:

• Chichewa Contempary Chichewa translation, 2002/2016:
  “Remember, You Jehovah, what the Edomites did
  on the day that Jerusalem was defeated.
  They shouted that, ‘Bring him down, bring him down
  up to his foundation!’” (Source: Mawu a Mulungu mu Chichewa Chalero Back Translation)
• Newari:
  “O LORD,
  when the Babylonians took possession of Jerusalem,
  remember what the Edomites did.
  They said "bury it, destroy it to its foundations."” (Source: Newari Back Translation)
• Hiligaynon:
  “Remember, LORD, what the Edomnon did when Babilonia seized Jerusalem/took- Jerusalem -by-force.
  They said, ‘[You (plur.)] destroy that completely.’” (Source: Hiligaynon Back Translation)
• Laarim:
  “LORD, you remember what the people of Edom did,
  during the day when Jerusalem was destroyed.
  They spoke by said that, ‘Let us destroy, Jerusalem,
  until it reach where it was dug.’” (Source: Laarim Back Translation)
• Nyakyusa-Ngonde (back-translation into Swahili):
  “Ee BWANA, ukumbuke jinsi walivyofanya watu wa Edomu,
  siku ile wakati Yerusalemu amekamatwa katika utumwa.
  Walisema, ‘Bomoeni!
  Bomoeni mpaka katika misingi yake!’” (Source: Nyakyusa Back Translation)
• English:
  “Yahweh, punish the people of the Edom people-group
  for what they did on the day that the army of Babylon captured Jerusalem.
  Do not forget that they said,
  ‘Tear down all the buildings! Destroy them completely! Leave only the foundations!’” (Source: Translation for Translators)