When you ask Siri a question, here’s what happens: Your voice is digitized and transmitted to an Apple server in the Cloud while a local voice recognizer scans it right on your iPhone. Speech-recognition software translates your speech into text. Natural-language processing parses it. Siri consults what tech writer Steven Levy calls the iBrain—around 200 megabytes of data about your preferences, the way you speak, and other details.
