I'm sure most people have seen this sign from time to time:
WARNING
HAZCHEM
For some reason best known to my subconscious, I always assumed (without having really thought too much about it) that 'hazchem' was Hebrew for 'warning'. It was only when someone asked me if I knew any words in Hebrew and I told them this word, and they asked how I knew it, that I realised mid-explanation how unlikely it actually was that English building firms would display that (and only that) notice in bilingual English-Hebrew form.