A list...

1. Mama
2. Dada
3. Nana
4. Nani
5. Cheese
6. Duck`
7. Wawa
8. Ice
9. Out
10. Tea
11. Jon
12. Joe-Joe
13. Hot!
14. Bus
15. Moo!
16. Cluck cluck

Whatcha! 8 words by 18 months - no sweat.

And signs?

1. Milk
2. More
3. Hi
4. Bye
5. Doggie
6. Fish
7. Kitty
8. Eggs
9. Eat
10. Drink
11. Ball
12. Big
13. Up
14. Down
15. Please 
16. Thank you
17. Train
18. Monkey
19. Alligator
20. Elmo (I am pretty sure he made up a sign for elmo that has NOTHING to do with Elmo)

I'm sure there are more of these and even some that we havent noticed.