Go to Settings > Voice, to enable the dictation feature. You can also configure your smartphone to automatically read incoming SMS (when headset is connected).
When you install new applications, they will add their own commands to those already present.
Sometimes you will see a microphone icon in certain text fields, as it is the case for Bing search. **Tap on this icon to switch to switch to speech recognition mode.
To get an idea of all the commands available on your Windows Phone, access the wizard by pressing the Windows button for a couple of seconds and then press the question mark button.
Voice recognition on Android
Since the last update ("Ice Cream Sandwich"), voice recognition on Android has been significantly improved: it is possible to visualize the texts that appear on the screen in real time and this feature has been extended to many compatible applications.
Some Android apps (built-in or downloadable) take advantage of speech recognition to perform various tasks:
Google Voice Search: This application allows users to perform searches on their smartphone or internet using voice commanda(e.g keywords, search for nearby places if the GPS is enabled).
Vlingo (on Android): This application allows you to dictate text messages, set an alarm, publish updates on Twitter and Facebook, get directions, take notes, etc..
Notepad Voice Memo: an application for taking notes
Notepad Voice Memo : a professional application to create to-do list.
Voice Recognition on iOS - Siri
What is Siri?
Siri is an intelligent personal assistant launched in 2011 and is compatible with all Apple smartphones as from the iPhone 4S.
It is based on three combined technologies
Advanced speech recognition,
Natural language processing (recognition of complex statements. For example: "Is there an Italian restaurant in the area"?)
Speech synthesis: the assistant answers to user queries.
Possible actions with Siri
Here are some examples of possible actions that can be initiated with Siri:
looking for information about your contacts (address, phone number, etc..)
sending messages (SMS, e-mails)
initiate telephone calls,
voice search for nearby places: restaurants, museums, ATMs etc.
publish messages (update status) on Facebook and Twitter.