To reduce system cost and eliminate the extra package required for the Audience chip, Apple cut a deal to integrate the noise-reduction technology directly into its A5 processor, which appears in the iPhone 4S. This technology is critical for the new phone because not only does it improve call quality, it blocks out background noise when users provide voice commands to Siri, the intelligent assistant built into the iPhone 4S. Without this noise reduction, Siri would be unusable even with a modest amount of background noise.
Recently I had installed Dragon Search and Dragon Dictation on my 3GS. While the underlying software that power these apps and Siri are from Nuance, the above finding by The Linley Group could be a reason why Nuance’s Dragon software titles have difficulties in a crowded room in my phone.
Apple is of course known to refrain from introducing or featuring technologies and abilities that have yet to meet its own threshold of acceptable performance in its products.
Another reason that have come up in the past for the lack of Siri in older products was the possibility that because Siri is still in beta, the company may be testing and collecting data to eventually deliver a more complete experience.
Of course, should Apple offer Siri in older iPhones, the value of iPhone 4S will be diminished greatly, and Apple certainly doesn’t want that to happen given that the company still sells the 3GS and 4 for the lower end of the market.
Internationally though, it makes little difference since Siri doesn’t offer much of an assistance beyond dictation and personal reminders outside of the United States at the moment anyway. Additionally, its linguistic limitations makes Siri practically unusable in many markets.