Ever heard of Augmented Reality? Well, it's going to be a big part of mobile phones and mobile learning over the next few years, and the immediate application to language learning should be obvious to everyone when you know what it is.
The best way to explain Augmented Reality (AR) is via films like Terminator and Robocop. You know how when the robot looks at something' loads of information (type of criminal, threat level, encyclopedia-type info about what he's seeing etc) pops up in front of his eyes. AR is a bit like that, but instead the information is received through a mobile phone's camera and displayed on its screen. The best way to show you this is through some videos. The first one is a demo of a program called Wikitude, which uses the phones camera and GPS to give you information about the place or building you are looking at. Although the info is in German, you can still get the basic idea:
This video shows Google Goggles, an application on your phone which recognises objects/text and then searches the web for information about it.
This one is very cool. This uses the phones GPS/camera to find info about real estate in the vicinity.
And this last one is particularly interesting as it has direct relevance to language learning. This program can take text in photos and translate it into whatever language you want:
I think these applications are going to be amazing for language learners. When they are out and about in foreign countries, they can take pictures of menus/instructions/adverts that confuse them and either get definitions or translations. It's a great way for them to research stuff in English (if that's the language they are learning) and learn more about the country they are in.