Following are a number of back-translations as well as a sample translation for translators of Jeremiah 15:19:

• Kupsabiny: “So God said to me,
  ‘When you return to me I will return you to stay like before
  and do work for me again.
  If you speak important words and not stupidness
  you will become my prophet.
  Let people come to you
  but do not join/follow their customs.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “Therefore the LORD said to me, ‘If you (sing.) repent, I will-cause you (sing.) -to-return to me so-that you (sing.) can continue to serve me. If you (sing.) speak useful things and not worthless things, you (sing.) will-become my spokesman/speaker. (It is a) need that they will-be- the -ones -to-take-refuge in you (sing.), and not you (sing.) will-be the one to take-refuge in them.” (Source: Hiligaynon Back Translation)
• English: “Then Yahweh replied,
  ‘If you begin again to trust in me,
  I will restore you,
  in order that you can continue to serve me.
  If you proclaim good/valuable messages and not worthless ones,
  you will continue to be the one who speaks what I tell you to say.
  You must cause the people to pay attention to what bd +w you;
  you must not pay attention to what bd +w they.” (Source: Translation for Translators)