Y'heard?

I've been on a mission to get the kid to use "y'heard?" as one of his first phrases.  If for no other purpose than to one day hear him eventually belt out, "Mommy, milk! Milk!  Y'heard?"   Now, I'm no expert at child linguistics, so my basic approach has been to punctuate almost everything I say around the baby with "y'heard?".    "I'm gonna change your diaper.  Now hold still, y'heard?" "Quit shaking that bottle, y'heard?" "Are we having fun on the swing, y'heard?"  (This last one doesn't really make sense, but it emphasizes how hard I'm trying with this, and how it's permeated every part of my dialogue with my child.)   Sometimes I feel guilty about doing this.  It's like I'm treating the rearing of my boy like one big practical joke.  I really don't want a smartass kid. I'm just worried about when he's 12, and saying "y'heard?", and it's no longer cute, maybe, just maybe, I'll have to admit I had a bad idea.