Following are a number of back-translations as well as a sample translation for translators of Jeremiah 9:4:

• Kupsabiny: “Each person should be on guard against his neighbor,
  and no one can even trust his brother,
  because each of them is a liar
  and (he) betrays/backbites his friend.” (Source: Kupsabiny Back Translation)
• Hiligaynon: “‘You (plur.) beware of your (plur.) fellowmen, and do not trust even to your (plur.) relatives, for each one is a deceiver and makes-up-accusations.” (Source: Hiligaynon Back Translation)
• English: “Do not trust your neighbors and even your brothers!
  They all are as deceitful as Jacob was.
  They slander each other and tell lies about each other.” (Source: Translation for Translators)