Dois has been using sign language for many months now, but it seems that we're going through a new "language explosion" involving signs. Before we used to just get the signs, but now he's applying the words to the signs as well.
This morning in the car the sun was in his eyes. He kept pointing out the window and signing "sun" and then saying, "sun"! Our morning drives are filled with signs as he observes things from his car seat. Dog in the car next to us? He signs "dog" and says, "Dog!" pointing to it. Loud car next to us? He signs "car" and makes a grumbling sound.
Bebe was about this age when we started using sign language with her. With Dois we've been teaching him since about 6 or 7 months old... and it's really paid off! I'd say he has about 100 signs in his vocabulary. We just love the Baby Signing Time series!