Hallie is 3 too and has just discovered the fun of rocks! We were walking the other day and she picked up a stick, spit it out, and grabbed a rock. I tried to get it our of her mouth but she thought it was a game so she spit it out (and I mean that, she spits things far) and we kept walking and suddenly she stopped, looked at me, and ran back the other way to get her "pet rock"! She then had a fit when I wouldn't let her bring it in the house!
I wish my dogs were bilingual too, that is so great you trained her in french! what a lucky dog