This video explains the American Idiom, "Break a Leg", which basically means "good luck!".

But there's another concept addressed in the video--the idea of "jinxing" someone.   A "jinx" is like what some cultures call an "evil eye".   The Italians call it "malocchio" which Italian Americans have turned into, "malooks"--bad luck.   If you "jinx" someone who give them bad luck.   Our superstition--a common one across cultures--is that if you say a good thing, it might not happen.   So you say, "Break a leg!"  its a superstion so you don't "jinx" someone--give them bad luck in whatever they're trying to accomplish.

All right?   All right.   And if you are interested at all in ESL or accent reduction lessons for yourself,  give me a call or text--text is fine if you are uncomfortable speaking on the phone--at 732-807-5424.   I look forward to hearing from you.  And remember to check out my David Berlin ESL YouTube channel.  For general info on me and my services and rates, check out my ESL and Accent Reduction Training Webpage.