Apple to Advance iPhone with both Text-to-Speech & Speech-to-Text Converters - Patently AppleThe user is offered the possibility of communicating with the incoming phone call using text-to-speech and speech-to-text capabilities. If receiving a phone call in a loud restaurant or quiet meeting, you might be able to choose the ability to answer using text messaging. The text would later be then turned into speech for the caller to hear, and the caller's verbal responses would likewise be converted back into text.
This could really be helpful to deaf people, too! Not needed to write note or speak from hearing person.