Even though I know better I still say "on your left". I think it is because I slow down, and actually enjoy watching the reactions. It's a MUP - I'm in no hurry if there are people present.

Kids ALWAYS swerve to the left, it's because they turn their heads to look and their hands follow (riding trikes or small bikes) just like every noob who is learning how to look back without swerving. I always plan ahead by slowing, early warning, consistant warning in a clear voice, and always have an escape route. Bike don't melt if they go off the path.

BTW - the comments about what exactly to say really are meaningless. I ride in an area where 9 out of 10 users don't speak English as a native language (mostly hispanic, Polish, Russian, etc.). They don't even understand what you're yelling, and you get the same kind of confusing reactions.

Nothing like watching 2 nice older ladies bump into each other because the one on the right goes left and the one on the left goes right. Especially when they have a good sense of humor. Everyone leaves that situation laughing.

BTW - does anyone know the Spanish equivalent of "On your left?" Is it "a las dereicho?" - sorry it's been a while....