Siri (pronounced /ˈsɪri/) is a virtual assistant that is part of Apple Inc.'s iOS, iPadOS, watchOS, macOS, tvOS and audioOS operating systems^[1][2] The assistant uses voice queries and a natural-language user interface to answer questions, make recommendations, and perform actions by delegating requests to a set of Internet services. The software adapts to users' individual language usages, searches, and preferences, with continuing use. Returned results are individualized.

Siri is a spin-off from a project originally developed by the SRI International Artificial Intelligence Center. Its speech recognition engine was provided by Nuance Communications, and Siri uses advanced machine learning technologies to function. Its original American, British, and Australian voice actors recorded their respective voices around 2005, unaware of the recordings' eventual usage in Siri. The voice assistant was released as an app for iOS in February 2010, and it was acquired by Apple two months later. Siri was then integrated into iPhone 4S at its release in October 2011. At that time, the separate app was also removed from the iOS App Store. Siri has since become an integral part of Apple's products, having been adapted into other hardware devices over the years, including newer iPhone models, as well as iPad, iPod Touch, Mac, AirPods, Apple TV, and HomePod.

Siri supports a wide range of user commands, including performing phone actions, checking basic information, scheduling events and reminders, handling device settings, searching the Internet, navigating areas, finding information on entertainment, and is able to engage with iOS-integrated apps. With the release of iOS 10 in 2016, Apple opened up limited third-party access to Siri, including third-party messaging apps, as well as payments, ride-sharing, and Internet calling apps. With the release of iOS 11, Apple updated Siri's voices for more clear, human voices, started supporting follow-up questions and language translation, and additional third-party actions.

Siri's original release on iPhone 4S in 2011 received mixed reviews. It received praise for its voice recognition and contextual knowledge of user information, including calendar appointments, but was criticized for requiring stiff user commands and having a lack of flexibility. It was also criticized for lacking information on certain nearby places, and for its inability to understand certain English accents. In 2016 and 2017, a number of media reports have indicated that Siri is lacking in innovation, particularly against new competing voice assistants from other technology companies. The reports concerned Siri's limited set of features, "bad" voice recognition, and undeveloped service integrations as causing trouble for Apple in the field of artificial intelligence and cloud-based services; the basis for the complaints reportedly due to stifled development, as caused by Apple's prioritization of user privacy and executive power struggles within the company.^[3]

Siri is a spin-out from the SRI International Artificial Intelligence Center, and is an offshoot of the US Defense Advanced Research Projects Agency's (DARPA)-funded CALO project.^[4] It was co-founded by Dag Kittlaus, Tom Gruber, and UCLA alumnus Adam Cheyer.^[4]

Siri's speech recognition engine was provided by Nuance Communications, a speech technology company.^[5] This was acknowledged by neither Apple nor Nuance for years,^[6][7] until Nuance CEO Paul Ricci confirmed the information at a 2011 technology conference.^[5] The speech recognition system makes use of sophisticated machine learning techniques, including convolutional neural networks and long short-term memory.^[8]

The initial Siri prototype was implemented using the Active platform, a joint project between the Artificial Intelligence Center of SRI International and the Vrai Group at Ecole Polytechnique Fédérale de Lausanne. The Active platform was the focus of a PhD thesis led by Didier Guzzoni, who joined Siri as its chief scientist.^[9]

Apple's first notion of a digital personal assistant was originally a concept video in 1987, called the Knowledge Navigator.^[10][11]

The original American voice of Siri was provided in July 2005 by Susan Bennett, unaware that it would eventually be used for the voice assistant.^[12][13] A report from The Verge in September 2013 about voice actors, their work, and machine learning developments, made hints that Allison Dufty was the voice behind Siri,^[14][15] though this was disproven when Dufty wrote on her website that she was "absolutely, positively not the voice of Siri."^[13] Citing growing pressure, Bennett revealed her role as Siri in October, and her claim was proven by Ed Primeau, an American audio forensics expert.^[13] Apple has never confirmed the information.^[13]

The original British male voice was provided by Jon Briggs, a former technology journalist.^[12] Having discovered that he was the voice of Siri by watching television, he first spoke only about his role in November 2011, also acknowledging his voice work was done "five or six years ago" without knowing the recordings' final usage form.^[16][17]

The original Australian voice was provided by Karen Jacobsen, a voice-over artist known in Australia for her work as the GPS girl.^[12][18]

As part of an interview between all three voice actors and The Guardian, Briggs stated that "the original system was recorded for a US company called Scansoft, who were then bought by Nuance. Apple simply licensed it."^[18]

With iOS 11, Apple auditioned hundreds of candidates to find a new female voice, then recorded hours of speech, including different personalities and expressions, and built a new text-to-speech voice based on deep learning technology.^[19]

Siri was originally released as a stand-alone application for the iOS operating system in February 2010, and at the time, the developers were also intending to release Siri for Android and BlackBerry devices.^[20] Two months later, Apple acquired Siri.^[21][22][23] On October 4, 2011, Apple introduced the iPhone 4S with a beta version of Siri.^[24][25] After the announcement, Apple removed the existing standalone Siri app from App Store.^[26] TechCrunch wrote that, despite the Siri app's support for iPhone 4, its removal from App Store might also have had a financial aspect for the company, in providing an incentive for customers to upgrade devices.^[26] Third-party developer Steven Troughton-Smith, however, managed to port Siri to iPhone 4, though without being able to communicate with Apple's servers.^[27] A few days later, Troughton-Smith, working with an anonymous person nicknamed "Chpwn", managed to fully hack Siri, enabling its full functionalities on iPhone 4 and iPod Touch devices.^[28] Additionally, developers were also able to successfully create and distribute legal ports of Siri to any device capable of running iOS 5, though a proxy server was required for Apple server interaction.^[29]

Over the years, Apple has expanded the line of officially supported products, including newer iPhone models,^[30] as well as iPad support in June 2012,^[31] iPod Touch support in September 2012,^[32] Apple TV support, and the stand-alone Siri Remote, in September 2015,^[33] Mac and AirPods support in September 2016,^[34][35] and HomePod support in February 2018.^[36][37]

Venture capital firm Mangrove Capital Partners predicted that Apple will launch a SiriOS at its developer conference in 2020 to further grow the Siri ecosystem. SiriOS could rival something like Amazon's Alexa Skills platform, which makes it easy for developers to implement Alexa functionality. Apple currently offers SiriKit to developers, but one possibility is that a SiriOS could work across iOS, iPadOS, and macOS with ease.^[38]

Apple offers a wide range of voice commands to interact with Siri, including, but not limited to:^[39]

Siri also offers numerous pre-programmed responses to amusing questions.^[40] Such questions include "What is the meaning of life?" to which Siri may reply "All evidence to date suggests it's chocolate"; "Why am I here?", to which it may reply "I don't know. Frankly, I've wondered that myself"; and "Will you marry me?", to which it may respond with "My End User Licensing Agreement does not cover marriage. My apologies."^[41][42]

Initially limited to female voices, Apple announced in June 2013 that Siri would feature a gender option, adding a male voice counterpart.^[43]

In September 2014, Apple added the ability for users to speak "Hey Siri" to enable the assistant without the requirement of physically handling the device.^[44]

In September 2015, the "Hey Siri" feature was updated to include individualized voice recognition, a presumed effort to prevent non-owner activation.^[45][46]

With the announcement of iOS 10 in June 2016, Apple opened up limited third-party developer access to Siri through a dedicated application programming interface (API). The API restricts usage of Siri to engaging with third-party messaging apps, payment apps, ride-sharing apps, and Internet calling apps.^[47][48]

In iOS 11, Siri is able to handle follow-up questions, supports language translation, and opens up to more third-party actions, including task management.^[49][50] Additionally, users are able to type to Siri,^[51] and a new, privacy-minded "on-device learning" technique improves Siri's suggestions by privately analyzing personal usage of different iOS applications.^[52]

Siri received mixed reviews during its beta release as an integrated part of iPhone 4S in October 2011.

MG Siegler of TechCrunch wrote that Siri was "great," praising the potential for Siri after losing the beta tag:

Writing for The New York Times, David Pogue also praised Siri's language understanding and ability to understand context:

Jacqui Cheng of Ars Technica wrote that Apple's claims of what Siri could do were bold, and the early demos "even bolder":

While praising its ability to "decipher our casual language" and deliver "very specific and accurate result," sometimes even providing additional information, Cheng noted and criticized its restrictions, particularly when the language moved away from "stiffer commands" into more human interactions. One example included the phrase "Send a text to Jason, Clint, Sam, and Lee saying we're having dinner at Silver Cloud," which Siri interpreted as sending a message to Jason only, containing the text "Clint Sam and Lee saying we're having dinner at Silver Cloud." She also noted a lack of proper editability, as saying "Edit message to say: We're at Silver Cloud and you should come find us," generated "Clint Sam and Lee saying we're having dinner at Silver Cloud to say we're at Silver Cloud and you should come find us."^[55]

Google's executive chairman and former chief, Eric Schmidt, conceded that Siri could pose a competitive threat to the company's core search business.^[56]

Siri was criticized by pro-choice abortion organizations, including the American Civil Liberties Union (ACLU) and NARAL Pro-Choice America, after users found that Siri could not provide information about the location of birth control or abortion providers nearby, sometimes directing users to pro-life crisis pregnancy centers instead.^[57][58][59]

Natalie Kerris, a spokeswoman for Apple, told The New York Times:

In January 2016, Fast Company reported that, in then-recent months, Siri had begun to confuse the word "abortion" with "adoption", citing "health experts" who stated that the situation had "gotten worse." However, at the time of Fast Company's report, the situation had changed slightly, with Siri offering "a more comprehensive list of Planned Parenthood facilities", although "Adoption clinics continue to pop up, but near the bottom of the list."^[61][62]

Siri has also not been well received by some English speakers with distinctive accents, including Scottish^[63] and Americans from Boston or the South.^[64]

In March 2012, Frank M. Fazio filed a class action lawsuit against Apple on behalf of the people who bought iPhone 4S and felt misled about the capabilities of Siri, alleging its failing to function as depicted in Apple's Siri commercials. Fazio filed the lawsuit in California and claimed that the iPhone 4S was merely a "more expensive iPhone 4" if Siri fails to function as advertised.^[65][66] On July 22, 2013, U.S. District Judge Claudia Wilken in San Francisco dismissed the suit but said the plaintiffs could amend at a later time. The reason given for dismissal was that plaintiffs did not sufficiently document enough misrepresentations by Apple for the trial to proceed.^[67]

In June 2016, The Verge's Sean O'Kane wrote about the then-upcoming major iOS 10 updates, with a headline stating "Siri's big upgrades won't matter if it can't understand its users":

Also writing for The Verge, Walt Mossberg had previously questioned Apple's efforts in cloud-based services, writing:^[69]

In October 2016, Bloomberg reported that Apple had plans to unify the teams behind its various cloud-based services, including a single campus and reorganized cloud computing resources aimed at improving the processing of Siri's queries,^[70] although another report from The Verge, in June 2017, once again called Siri's voice recognition "bad."^[71]

In June 2017, The Wall Street Journal published an extensive report on the lack of innovation with Siri following competitors' advancement in the field of voice assistants. Noting that Apple workers' anxiety levels "went up a notch" on the announcement of Amazon's Alexa, the Journal wrote: "Today, Apple is playing catch-up in a product category it invented, increasing worries about whether the technology giant has lost some of its innovation edge." The report cites the primary causes as being Apple's prioritization of user privacy, including randomly-tagged six-month Siri searches, whereas Google and Amazon keep data until actively discarded by the user, and executive power struggles with some employees leaving. Apple declined to comment on the report, while Eddy Cue said: "Apple often uses generic data rather than user data to train its systems and has the ability to improve Siri's performance for individual users with information kept on their iPhones."^[3][72]

The iOS version of Siri ships with a vulgar content filter; however, it is disabled by default and must be enabled by the user manually.^[73] Therefore, if Siri can be triggered into cursing, broadcasting discriminatory content, and so on, the actions will most likely be carried out. Over its history, multiple methods and techniques have been used to trigger Siri into swearing. The language-filter is not perfect and can still be bypassed.

In 2018, Ars Technica reported a new glitch that could be exploited by a user requesting the definition of "mother" be read out loud. Siri would issue a response and ask the user if they would like to hear the next definition; when the user replies with "yes," Siri would mention "mother" as being short for "motherfucker."^[74] This resulted in multiple YouTube videos featuring the responses and/or how to trigger them. Apple fixed the issue silently, although it is unconfirmed if the videos specifically brought it to their attention. The content is picked up from third-party sources such as the Oxford English Dictionary and not a supplied message from the corporation.^[75][76] It is unknown whether this glitch was exploited with the vulgar content filter enabled.

Siri provided the voice of 'Puter in The Lego Batman Movie.^[77]