Following are a number of back-translations as well as a sample translation for translators of Proverbs 27:3:

• Kupsabiny: “A stone and sand are heavy alright,
  but when a foolish person gets angry/annoying it is very heavy/difficult for people.” (Source: Kupsabiny Back Translation)
• Newari: “Rocks and sand are heavy.
  But the trouble which fools make
  is the heaviest of all.” (Source: Newari Back Translation)
• Hiligaynon: “Stone and sand are heavy, but it is more hard/[lit. heavy] to emotionally-feel if a foolish man provoke- you (sing.) -to-anger.” (Source: Hiligaynon Back Translation)
• Kankanaey: “Stones and gravel are heavy, but the problems that a foolish-person causes-to-be are heavier.” (Source: Kankanaey Back Translation)
• English: “It causes pain to our bodies to carry heavy stones or a pail full of sand,
  but doing something stupid/foolish can cause great pain to other people’s spirits.” (Source: Translation for Translators)