Following are a number of back-translations as well as a sample translation for translators of Zephaniah 3:18:

• Kupsabiny: “The God of power says,
  ‘You (sing.) were not happy because you were unable to celebrate the feasts.
  But I am giving you happiness.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “like a man/person who rejoices on the day of feast.’
  ‘The LORD says, ‘I will-take-away your (plur.) suffering so-that you (plur.) no-longer be-put-to-shame.” (Source: Hiligaynon Back Translation)
• Newari: “‘I will gather those of yours
  who grieve over the appointed feasts
  and bear the burden of shame.” (Source: Newari Back Translation)
• Burmese (translation by A. Judson): “The cause of your bearing the burden of reproach will be far from you and
  I will assemble those who are dejected and cannot take part in the sacred festival.” (Source: John Hans de Jong in The Bible Translator 2017, p. 64ff. )
• English: “Yahweh says, ‘You people were sad and ashamed
  because you were unable to attend your religious festivals;
  but I will cause you to no longer be disgraced.” (Source: Translation for Translators)