Just thought you guys might like to hear what I hear all the time now when Caleb is playing. He has become quite the noisy, chatty little boy so there is rarely peace and quiet in the house (not that there ever was)! :)
In reality, I actually think that Caleb is really trying to say hi (which is not evidenced by this video). It comes out as a conglomeration of "hi" and "hey" but he seems to say it pretty consistently when he sees somebody or in response to them saying hi to him! It could be coincidence, but I prefer to think that it's not.