Whether you want to avoid the hassle of the tiny touch-sensitive keyboard of the iPhone 4 or are unable to type, you can opt instead to use voice-activated typing. Several third-party developers have built apps for this purpose. Some apps are specifically designed for certain tasks, such as texting or searching, while others are more generic, similar to dictation software.
Speech-to-text, or speech recognition, is the process by which a computer translates the spoken word to visual text. First appearing in the 1950s, it has been an important medical breakthrough for assisting the physically impaired. Speech-recognition software can also be used to perform specific tasks, such as voice dialing, automated customer-service calls, or voice-activated security. It also has several military applications, and it can be used for automated realtime translations.
If you want generic text-to-speech software for your iPhone, you have two available app choices as of 2011 in the App Store: Dragon Dictation or Vlingo. Dragon Dictation is free while Vlingo charges for texting and email, but Vlingo offers slightly more advanced features. With Dragon, you can tap a button to record your speech, then you can select where you want to post or send that text, whether it be in an SMS message or on Facebook. With Vlingo, you can give spoken commands, so if you want to email someone, you can simply say "Email (name), subject (your subject line), message (your message). Send." Vlingo comes with a wide array of features, including maps, web search, social updates and voice dialing.
If you simply want to be able to "type" a search term by speaking it, also known as voice-activated searching, you have several options. Many major search engines provide an app with spoken-search technology, including Google Search, Bing and Yahoo Mobile. Third parties also offer search-only speech-to-text apps, such as Dragon Search and Ziplocal. With these apps, you can open the app, tap the search bar and speak the word or phrase that you want to search.
Typing a text while driving is a dangerous activity. Fortunately, many apps are specifically designed to avoid this risk by allowing you to speak the entire process of receiving, writing and sending a text. One of the most commonly used apps is Voice Text Pro, which is the only app that allows you to send texts for free as of 2011. With this app, you can speak a contact's name, speak your message, and then hit send.