Hmm
I suppose it kind-of defeats the purpose if we never correct each other, but not many like to be corrected... I've seen in a grammar community abroad that people correct each other by writing the correction in brackets at the end of a (relevant) reply---I thought that was a nice way to go about correcting others. Another idea is to write something similar in a correct way. The important thing is to respect others and realise that hardly anyone speaks English perfectly. What do others think? By the way, `רוקד' technically is a participle (there's no real present tense in Hebrew), so Ferma[t] wasn't entirely wrong (except with spacing and capitalisation)