Apple recently filed a patent application for a text-to-speech and a speech-to-text converter designed to work in noisy environments. The patent describes a system that uses a converter included on the logic board of the phone. This hardware-based conversion would have a distinct advantage over current text-to-speech systems, which use an internet-based service from a company like Nuance to translate conversions.
Unlike Android's text-to-speech system, which is used for searching and navigation, Apple's patent describes a system used for sending and receiving phone calls. In one embodiment, a microphone on the iPhone would detect the ambient noise level and prompt the user to answer a call using text-to-speech in a noisy environment when talking on the phone may be difficult. The person answering the call would type in their messages, and the phone would convert it to speech heard by the caller.
In another example, the user could choose to talk via a two-way texting system that uses both text-to-speech and a speech-to-text within the conversation. Basically, your caller's words would be converted to text that you could read, and you could input a text response that is converted to speech for the caller on the other end. It's an elegant system that would be useful for making phone calls at a loud sporting event or a crowded bar.
Apple is rumored to be in talks with Nuance that could bring an advanced speech recognition system to iOS. This above patent may describe a small part of what is to come for iPhone owners in the future.