The biggest "game changing" feature of the iPhone 5 is tipped to be Assistant, an evolution of Voice Control which lets users record reminders and send text messages by speaking to their phone, according to tech site 9to5mac.com.

Activated by holding down the home button for a couple of seconds, a microphone slides up from the icon, the user can then say a whole range of commands, such as "how do I get to Starbucks?" or "send a text to Mark to say I'm running late for lunch".

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Assistant will use any information stored in your phone such as contact addresses, GPS location, calendar entries and items on your to-do list in the new Reminders app, to fulfil your commands.

"This is a super compelling feature for people who cannot physical or safely take the time to type out a text message," writes 9to5mac.com, "Users can also choose to have Assistant read back unsent text messages to ensure the system interpreted the speech correctly."

Assistant can even hold a conversation with its owner - acting like a personal assistant who can arrange meetings and interviews with your instructions. "If a user is making a meeting, they will say "setup a meeting with Mark" and the first 'bubble' of the conversation will say that. After that, the system will speak back: "which email address should Mark be notified at, work or personal?" This question will both be spoken out loud by the iPhone Assistant and shown as a new 'bubble' in the conversation thread."

This level of speech recognition and computing power means that, according to 9to5mac.com, only the iPhone 5 will be able to support Assistant; iPhone 4 and 3GS users will not get this feature.

The tech blog continues: "The speech interpretation is so accurate that users do not even have to speak very clearly or in a slow and robotic tone, according to a source familiar with the software. Users can simply talk how they would usually talk to another person, and the iPhone with Assistant will do its best to interpret the speech and provide accurate results."

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Also tipped to be included in Assistant is integration with online computational knowledge system Wolfram Alpha, which can answer maths problems instantly. For example, a user could ask Assistant "how many feet are there in 12.75 meters?" and their iPhone would answer right away - providing it has a data connection, obviously.

The latest hardware rumours suggest that the iPhone 5 will feature a dual-core A5 processor, 1GB of RAM, and an eight megapixel camera with the ability to take panoramic photographs.

Apple is reported to be announcing the new iPhone 5, along with iOS 5, a new iPod touch and iCloud at a media event on October 4.