Tim Cook presided over the voice launch event though, leaving it to Apple senior VP for world product marketing Phil Schiller (right), to introduce Siri reports Technology Review of  the  demonstrations at Apple's headquarters in Cupertino, California.  

Here Siri handled such questions as "What is the weather like today?" Response was both a display and speaking a forecast for the owner's current location). Asked conversationally, "Do I need a raincoat?" the Siri response: "It sure looks like rain today.

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Siri draws on a number of online sources of information, weather feeds to local business revie ands, search engine Wolfram Alpha. Siri can find restaurants in specific areas, book tables, or set alarms and set up meeting reminders to spoken orders and queries.



Siri technology originated in a DARPA-funded research Speech Technology and Research Laboratory project of SRI International  and was used to launch a startup company Nuance.  Apple bought Siri   iPhone app in 2009, buying the company in 2010.



A separate new feature, Dictation, allows users of the new iPhone to use speech recognition to compose text messages or e-mails.  This is already possible for users of Google's Android software for phones and tablets.



Both Siri and the Dictation feature were labeled as "beta" products. possibly because like all voice-recognition technology, that which Apple has licensed from the software company Nuance for both Siri and Dictation may not always be perfectly accurate.



Apart from Siri and Dictation, the new iPhone 4S is outwardly identical to the previous iPhone 4, but has improved components including a more powerful processor and an improved camera.



Norman Winarsky (left) of SRI International worked on the project that spawned Siri and was cofounder of the company that launched its original app. He says Siri's speech-based interface is not its most impressive feature.

"Recognising speech has become a commodity. It is finding the "intent" in what you said and matching that with the Web services available that cost hundreds of millions in research." Winarsky and colleagues at SRI made their technology capable of handling ambiguity and variability in statements, enabling Siri to deal with casual commands so that users don't have to use carefully scripted phrasing, he says.