Siri ships on the iPhone

Siri began as CALO, the Cognitive Assistant that Learns and Organizes, a five-year DARPA project run from SRI International, the laboratory that had built Shakey. In 2007 three of its researchers spun the assistant out as a company; Apple bought it in April 2010, and on 4 October 2011, the day before Steve Jobs died, announced it as the feature of the iPhone 4S. You held the button and asked, and the phone answered in a voice.

The speech recognition was licensed from Nuance and ran on servers; the understanding was a hand-built system of domains, restaurants, weather, reminders, each with its own grammar. It was often wrong and much mocked, and it was used by hundreds of millions of people, which no conversational system had been before. Google Now followed in 2012, Amazon's Alexa in 2014 and Microsoft's Cortana the same year.

The assistants promised more than the technology of 2011 could give, and for a decade they answered simple questions and set timers. When large language models arrived, Apple, which had shipped the first assistant, was slowest to rebuild it around them. Siri is on this timeline as the point at which speaking to machines became normal, ahead of the machines being worth speaking to.