Using the Short Messaging Service (SMS) functions on mobiles, people with hearing difficulties can communicate by typing messages into their phones.

BBC: Deaf go mobile phone crazy

And users can see when people are typing or when they sent messages, as they do with instant messengers.

FORBES: Connect

When the young members of Generation-i use their phones to send text messages, the small keyboards make typing awkward and abbreviations even more important: "b4n" (bye for now), "cu" (see you).

WSJ: David Gelernter: The Pros and Cons of Cyber-English