Following are a number of back-translations as well as a sample translation for translators of Jeremiah 31:13:

• Kupsabiny: “God is saying,
  ‘I will turn their mourning to become happiness
  and I will make their pain to become joy.
  Then their daughters will sing/dance with joy
  and their young men and old men will be happy.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “Their ladies and young-men as-well-as the old-ones will-dance for joy. I will-replace their crying with joy. Instead that they will-mourn, I will-comfort them.” (Source: Hiligaynon Back Translation)
• English: “The young women will dance joyfully,
  and all the men, young ones and old ones, will join with them.
  I will cause them to rejoice instead of mourning;
  I will comfort them and cause them to be happy instead of being sad.” (Source: Translation for Translators)