Following are a number of back-translations as well as a sample translation for translators of Joel 2:27:

• Kupsabiny: “You will realize that I am with you
  and you will again know that I am your God and there is no one else,
  and never in another day
  will my people be despised.’” (Source: Kupsabiny Back Translation)
• Newari: “Then you will know that I am in the midst of Israel,
  I am LORD your God.
  You will know that there is none other besides me.
  My people will never again have to live in shame.” (Source: Newari Back Translation)
• Hiligaynon: “Then you (plur.) will-know that I (am) here among you (plur.) who come-from-Israel, and I alone (am) the LORD your (plur.) God and there-is-no-one else/[lit. other yet]. And you (plur.) my people will- no-longer -be-put-to shame forever/[lit. until whenever].’” (Source: Hiligaynon Back Translation)
• Kankanaey: “At that time, you will-come-to-know that I am in the location of you Israelita and I am Yahweh your God, there-is-no other. Absolutely not again will my people be-shamed.’” (Source: Kankanaey Back Translation)
• English: “When that happens, you will know that I am always among you,
  and that I am Yahweh, your God,
  and that there is no other God.
  Never again will you be disgraced.’” (Source: Translation for Translators)