When Apple introduced the latest iteration of its smartphone, the iPhone 4S, in October, one of its new features was voice control through "intelligent assistant" Siri. Although voice control isn't exactly new to Apple's iPhone, as it was first introduced on the 3GS in 2009, we look at just what voice control is, how Siri differs from previous offerings and whether all iPhone users can get their hands on it.

What is an "intelligent assistant"?

Voice control is exactly how it sounds, you can make the phone do something by making an audible command. According to Apple, unlike traditional voice control which relies on the user speaking a specific command such as 'call mum' to dial a contact, Siri understands context and allows you to speak naturally when asking questions. For example if you say 'will I need an umbrella this weekend?' Siri will provide you with a relevant answer, in this case, the weather report. Furthermore, it's integrated into a number of different apps on the iPhone. The voice-control function that was available on previous versions of the smartphone only allowed voice dialling and control of music playback in the iPod feature.

However, our reviewer wasn't that impressed with the original voice control on the iPhone 3GS. "When I remained silent, Voice Control somehow managed to tease commands out of the empty air around me, including attempting to dial random people in my phone book," he said.
Siri has feared better and nearly always actually recognised what we actually said. Although, in the UK at least at the moment, Siri can't give directions, find business addresses – nor even tell you where you are. "And that's a big weakness we hope gets fixed soon", said our reviewers.

Unfortunately, while those with handsets earlier than the iPhone 4S can get their hands on most of the features in the new iteration of the smartphone through upgrading the operating system to iOS 5 via iTunes, the same doesn't apply to Siri. Furthermore, Siri Assistant - the app on which Siri is based (and which Apple acquired last year) – was removed by Apple from the App Store on October 15.

One hacker already claims to have a rudimentary version of Siri running on an iPhone 4. Ireland-based hacker Steve Troughton-Smith, who uncovered the iPhone's Internet tethering capabilities in 2009, was responsible for the hack. It's worth noting that Siri is a beta release and when Apple makes the final version available it may well extended the app's availability to older iPhones as well. However, for now we've got five alternatives to Siri that allow to control your iPhone by voice.

And what about if you've got an Android device? Handset running Google's Android version 2.2 can benefit from Voice Control that was released last year and allows users to make calls, send text messages and even get directions, search Google and listen to music by using audible commands. Although in my personal experience it has struggled to understand my ever-so-slight south London accent. However, this may all be set to change as Google is thought to be working on a Siri-rival called Majel.