I am a nanny for a 20 month old little boy and since I am not his guardian I cannot speak to his doctor. He understands everything I say. When I ask him to do something ie; please stop playing in the garbage, or after he gets mad and throws his cup or toy and I ask/encourage/help him pick it up he will not do it. He simply looks at me, crosses his arms and turns his back.he also will not use his words, and I know he can because he has said them before and uses them during play. He is making and surpassing all other milestones, but will NOT say; up,down, cup, drink, bite, more, please, or anything that can be said to express his needs or wants. He won't even say please for a French fry, unless its way after the fact and he thinks nobody is listening he will say please multiple times, when I hear him I praise him for saying please and give him something he likes ie; drink, bandana, cookie. Any sort of corrective phrase causes him to look at the floor and sometimes cry. I feel like he is very obstinate because I know he knows what he should do and not do. When he goes to do something he isn't supposed to do he looks to see if I will correct him, and I do, I'm very consistent with the rules.I have no idea what else there is to do.

Is this your first experience with a toddler? Have you heard of the "Terrible Twos"?

Change your way of reacting. You are being too predicable. Give me a few minutes to find an answer I gave to someone else, and will post it.

***ADDED*** I can't find it right this minute. It had to do with singing your reply to him or whispering to him or doing storytelling or making talking fun in various ways, always with a bright-happy-surprised look on your face. Use your imagination. Scolding and punitive measures will work against you (as you have noticed). And your public library has books on how to positively deal with toddlers at this age. Please check out a few.