Pat has a friend who can't speak and needs a device that he can type on, and then prints out to someone's mobile device so they can have a conversation. It also needs to be multi-lingual. Leo says that smartphones are great for that. He can use Apple Messages on the iPhone to do that. Leo recommends checking for Independent Living Resource Centers.
ScooterX in the chatroom says that TouchVoice is a great app for that. Price is about $14 and it'll work on iPhone, Android, and even the desktop. It will also have a voice playback so he doesn't have to worry about having to have a second device to use.