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

• Kupsabiny: “That day comes with darkness and fear/anxiety.
  Clouds will envelope the land and darkness cover it.
  Many soldiers will swarm against it,
  (they) will come quickly like when it dawns.
  They (being many) shall swarm on (it) which has never been seen any day (before)
  and never again shall others be seen like that.” (Source: Kupsabiny Back Translation)
• Newari: “A day of darkness and gloom,
  a day of clouds and blackness! Like the first appearance of
  dawn spreading upon the mountains
  a huge and strong army will come.
  There has never been anything like it before, and there will never be anything like it again.” (Source: Newari Back Translation)
• Hiligaynon: “That day (is) dark and has-dark-rain-clouds. The terrifying/terrible locusts which (are) very great-in-number are-spreading upon the mountains like the spreading of the shining of the sun when (it) is- already -dawning. Nothing has- ever -happened which (is) like that since time-past, and (it) will- no-longer -happen like that forever/[lit. until whenever].” (Source: Hiligaynon Back Translation)
• Kankanaey: “That-aforementioned day will-be-depressing, because it will be extremely dark and cloudy. Right then will arrive strong and uncountable soldiers like the sudden arrival of sunshine on the tops (lit. heads) of mountains. There-was-nothing similar to it that happened in the past and even in the coming time.” (Source: Kankanaey Back Translation)