Following are a number of back-translations as well as a sample translation for translators of Proverbs 15:20:

• Kupsabiny: “A wise child makes his parents happy,
  but a foolish one brings (them) shame.” (Source: Kupsabiny Back Translation)
• Newari: “A wise son makes his father glad,
  a foolish son scorns his mother.” (Source: Newari Back Translation)
• Hiligaynon: “A wise child gives joy to his parent. Foolish is a child who speaks-evil to his parents.” (Source: Hiligaynon Back Translation)
• Kankanaey: “The thinking/reflective child makes-happy his parent (lit. child originator). Only the fool mocks-belittles his origin (i.e., his parents).” (Source: Kankanaey Back Translation)
• English: “Children who are wise cause their parents to be happy;
  it is foolish children who despise their parents.” (Source: Translation for Translators)