Following are a number of back-translations as well as a sample translation for translators of Joel 2:15:

• Kupsabiny: “Blow (plur.) (a) horn on mount Zion
  and announce a fast.
  Call for a meeting of prayer,” (Source: Kupsabiny Back Translation)
• Newari: “Blow the trumpet in Zion!
  Announce a holy fast!
  call for a Holy Assembly!” (Source: Newari Back Translation)
• Hiligaynon: “[You (plur.)] sound the horn/trumpet in Zion to let- the people -know that they are-to-gather and fast.” (Source: Hiligaynon Back Translation)
• Kankanaey: “Blow-trumpet(s) on the mountain Zion so-that you will gather the collective-people and command that they restrain their hunger.” (Source: Kankanaey Back Translation)
• English: “Blow the trumpets on Zion Hill!
  Gather the people together!
  Show by fasting that you are sorry for the sins that you have committed.” (Source: Translation for Translators)