My son is a little over 2.5 years old, and I have taught him to approach a child and ask for the toy he was still using. He will almost alway try it, as long as I am close by. I will gladly step in to help him out if his request does not yield the desired effect, but I feel strongly that he should know that though he is still little, he and his words are powerful. Another motivating factor behind my doing this is that my son is in a child care situation, and I am obviously not there with him, so I wanted to teach him the skills he would need to advocate for himself. I started modeling this for him when he was only about 1 year old, and by the time he turned 2, I encouraged him gently to tell kids on the playground if he wanted his toys back. Perhaps becuase he gets the opportunity for lots of practice with children he does know well, he is more comfortable approaching a child he doesn't know.