Following are a number of back-translations as well as a sample translation for translators of Jeremiah 23:21:

• Kupsabiny: “God is saying,
  ‘I did not send those prophets,
  but they came on their own.
  I did not say anything to them,
  but they came/went out to prophesy.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “I did- not -send these prophets, but still they went. I did- not -speak to them, but they prophesied.” (Source: Hiligaynon Back Translation)
• English: “Yahweh also says, ‘I have not appointed those prophets,
  but they run around telling people their messages.
  I did not speak to them,
  but they continue to prophesy.” (Source: Translation for Translators)