This presentation from the 2011 TED conference last week has been going around, featuring MIT researcher Deb Roy describing "the ultimate memory machine," a data set containing some 90,000 hours of video and 140,000 hours of audio recorded by little cameras and mics spread throughout Roy's home. He says it's the largest collection of home movies ever made, and they're using the data, as it were, to explore a few things, including the process through which a child learns language. Tune in at about 4:25 in the video below for the good part -- where they distill 18 months of audio of his son going from "gaga" to saying the word "water" -- or watch the whole video if you're a nerd with time to kill.