Some recent favorites:
Eew (as in "yuck") - This is Olivia's word for any stray hair that she finds lying around. Usually she identifies it as "Daddy eeew" or "Mommy eeew" but sometimes she is willing to take the blame herself. For example in the bath today she found an eyelash and called it "Baby Olivia eeew"
Just like Olivia - This can be either a comment or an instruction. She is very aware of when people are doing the same thing. So if, for example, we are both wearing robes Olivia will say "Just like Olivia, just like Daddy." And if she wants you to do exactly what she is doing she will say with increasing volume, "Just like Olivia, just like Olivia, JUST LIKE OLIVIA!"
Two-Both - Most often used when Olivia wants to do the same thing to two people simultaneously. For example "Two-Both hug" (if she wants to hug Liz and I at the same time, or if she wants to make Liz and I hug each other.) It can also be generally used as a substitute for "two" or "both".
Sitalap - I want to sit on your lap.
One Day Baby Olivia - This is a request to tell the story of something sad that just happened. If Olivia is upset she likes us to tell her the story, sometimes multiple times. It helps her to know that we understand her.
She also sometimes requests specific stories. Her favorite is the story of when she shared her balloon with another baby named Bella. If she wants to hear that story she will ask, "One day Baby Olivia Bella balloon, please?"
Twenty-Ten - Olivia can count to twenty-ten! Her 1-10 is pretty consistent, but she usually skips a few numbers in the teens and twenties, probably because she's so excited about getting to twenty-ten. I know I would be.
Altogether - This proclamation is usually proceeded by a list of all the people (and/or objects) in the room. As an example, when we had some friends of ours for lunch over recently Olivia commented, "Mommy and Daddy and Baby Olivia and Amia and Suzanne and Husayn and-a ceiling and-a chips ALTOGETHER!"