Ernie seems to be learning new words all the time. He repeats us like crazy. Here's a running tab of words he can say recognizably, and apply correctly (please add to it in the comments, anyone who converses with Ernie, because I know I'll forget some):
Baby
Ball
Balloon ("boon")
Big Boy ("bee boi")
Books
Bowl
Bunnie
Bye Bye
Cat
Dad
Darren ("Dern")
Dirt
Dog
Done
Door
Dora (the Explorer, on the side of his yogurt container)
Elbow ("bow")
Eyes
Flowers (sounds like the French "fleurs")
Grandma ("Nama")
Grandpa ("Bampa")
Hat
Hi
Hot
Juice
Knee
Momma
Nose
Outdoor (which also means "out the door")
Pee Pee
Poop
Rowr (what anything other than dog's say)
Shoes
Spoon (sounds like "thspoo")
Toes
Tree ("tee")
Water (Wawr wawr)
Woof (what dog's say)
Yes