analogue audio must be converted into digital signals. This requires analog-to-digitalconversion. For a computer to decipher the signal, it must have a digital database, or vocabulary, of words or syllables, and a speedy means of comparing this data with signals. The speech patterns are stored on the hard drive and loaded into memory when the program is run. A comparator checks these stored patterns against the output of the A/D converter. This could be used for someone who struggles to use their hands on the phone or for someone who is blind. Siri is a good example of a voice recognition, however it is only available on iPhones. You can access it by holding down on the home button or you can go into settings and you can activate siri by just saying "hey siri" and it will talk back to you and ask what you need help with.