Jonathan has connected "Mommy" and "milk". When Gabe is holding him, and he's hungry, he'll cry until he catches sight of me - at which point he stops for a moment. Of course, if I'm not quick enough about actually feeding him, he'll start again...but he definitely understands the connection. I think that's pretty cool.
Gabe also thinks that Jonathan has some connections between being in the kitchen and expecting to see me. I do spend quite a bit of time in the kitchen with him. The other night I was late getting home, and Jonathan was hungry and upset, and Gabe said that when he went into the kitchen Jonathan would quiet down (just for a second!) and look around like he expected me to be there.