I've been waiting to see how the twins will talk to each other as they get older. Currently most of their interactions revolve around taking the other one's toy - even if they have the exact same toy in front of them. Then screaming ensues, the toy is given a time-out, and repeat.
But two nights ago, we had two very tired babies who did not want to sleep. Colin was making the most noise, so I picked him up and sat with him in the rocker. Keira, seeing that my attention was focused on her brother, sat up and sucked her thumb for about 30 seconds. After deciding that she was not happy being ignored (I was trying not to make eye contact in hopes she would lay back down), she burst into tears and loud wailing. Keith came up and got her out of bed. She wanted her mommy, so we switched babies, and went back to rocking.
Suddenly, Colin made a little noise, like a "hmpfh". A moment later, Keira made the same noise. Then Colin, then Keira, and repeat. It was the sweetest thing to hear. They were talking (or something) to each other. He had his pacifier, she had her thumb, and the room was filled with "hmphs". They continued like that for a few minutes, before they were placed in their beds (again).