I'm not sure, but whenever I tell him to give me his right/left hand, right/left foot, turn right, turn left, etc. etc. he always does. Maybe it's just coincidence, but we have been working with him on this for quite some time now.
My DS will say left and right and knows that they are some kinda direction (he will be 2 1/2 in january) but its usually a coincedence if he points or goes in the direction he is saying. I was gonna guess 4 yrs to kindergarten range but wasn't sure.
Re: Age for understanding left and right?