Counting is the new thing, now. One of their favorite books is "Rainbow Fish Counting" - it was included in the free tote bags that CPMC gave out to all the babies born at their hospital. Attached to it was a flyer about reading early and often to your baby. The girls especially like it when Daddy reads this book because he likes to count and point to the sea-animals on the page really fast and loud - like it is a race. His erratic and exaggerated counting always gets them giggling.
Even when Daddy isn't home, the girls will pick up that book, open it and start counting like they were Daddy. You can tell they're counting because of their methodic, monotones and synchronized pointing. When they read, they're not in any race, but, like Daddy, they often count the same animal multiple times and miss other ones entirely!
We also count when we're waiting for the milk to warm in the microwave. Tina will stand at the foot of the microwave, her finger pointing and waving methodically up and down saying a combination of gibberish and numbers. I suppose this ritual gives her some comfort or distraction of how soon the milk will actually come to her. When the timer finally beeps, both girls throw their wiggling hands in the air and say, "Yea!" just like their sign language.
From their car seats, they have also starting counting. The more they practice, the better they get. They know that to start counting, they use the word "one." They also know that "two" comes after "one." However, after that, they get a bit lost and just make up a bunch of numbers. The funny thing is, though, that when they're getting done with their counting, they always end with "nine, ten!"