By analyzing 8-9 million words of speech recorded over a two year period, Professor Deb Roy at the MIT Medialab was able to distinguish the exact moment that his son learned a new word. Taking that idea of a “word birth,” the study looked at the gestation period of a word. By tracking the use of a particular word - what was happening, where in the house were they, and how were they moving about - the visual information provided contexts in which the words were used. The study revealed that prior theories of speech development were incorrect.