He can also say truck, after a fashion -- it comes out "dk".
He is also coming along with his signing. He can make more signs than words, which helps him communicate and avoid frustration while he waits for his vocal control to develop. The first few signs took a while, but now he knows when to pay attention to learn a new sign. He's long known "milk" (like milking a cow), and "more" (fist hitting palm), but also knows "all done" (back-and-forth hand motion), "eat" (fist to mouth) and now "drink" (finger to mouth then tilt hand up), airplane (thumb and forefinger extended then hand moves back and forth -- and he points out every one!), fish (vertical wiggling hand), water (horizontal wiggling hand), and even flower (sniff sniff). He might know bird and light, but I'm not sure.
He knows what sounds the doggies make (wuh wuh wuh, very quietly). He knows what it means to go outside, and what a truck is (and we had better bring his with when we go outside).
He can answer "where's daddy's nose" and "where's mommy's bellybutton" (even if he has to lift a shirt to find it). The bellybutton thing he learned in just one day.