r/translator

If you speak more than one language, come help translate!

I'm checking one line in a children's book. A Polish-heritage boy quotes his grandmother's saying: "Kto połamał płot, ten wie, gdzie wisi młotek." The book translates it as "The one who broke the fence knows where the hammer hangs." It's meant to be her own folk-style saying, not a famous proverb. Is the Polish grammatically correct and natural-sounding for a grandmother? Is the spelling (including the special characters) exactly right? Would you word it differently? Thank you!