Following are a number of back-translations as well as a sample translation for translators of Proverbs 29:9:

• Kupsabiny: “If a wise person accuses a fool in a court,
  the foolish one will only bare his teeth (sneer/make fun of).” (Source: Kupsabiny Back Translation)
• Newari: “If a wise person goes to file a lawsuit against a fool,
  the fool will only laugh and jeer at him,
  nothing will come of it.” (Source: Newari Back Translation)
• Hiligaynon: “There is no [emphatic marker] destination/place-to-go if a wise man accuses a fool, for a foolish-one will- just -keep-on talking and mock.” (Source: Hiligaynon Back Translation)
• Kankanaey: “If a wise-person accuses-in-court a foolish-person, it is no use, because the foolish-person will just shout in his anger and mock/belittle.” (Source: Kankanaey Back Translation)
• English: “If a wise person sues a foolish person,
  the foolish person merely laughs at him and yells at him and will not be quiet (OR, the dispute will not be resolved).” (Source: Translation for Translators)