We love to speculate about future mobile phone features, and this is one that's got our imaginations racing. German researchers at the Karlsruhe Institute of Technology (KIT) have been beavering away on a project that converts mouth movements into speech. Rather than making any sounds, your handset would decipher the movements your mouth makes by measuring muscle activity, then convert this into speech that the person on the other end of the call can hear. So, basically, it reads your lips.

The potential for secret conversations just got huge. If it's a particularly dull film, you could pass the time by making phone calls from the cinema without disturbing anyone. In noisy places like bars and clubs you could feasibly make yourself heard without having to shout. The technology would be particularly handy if you've been taken hostage but managed to work your bound hands free enough to retrieve your secret mobile, dial and get your face close enough for the technology to work. In a more every-day sense, people who insist on calling everyone they know while travelling on public transport can do so without the rest of the train carriage hearing about "our Tina's troubles" and the associated unpleasantness.

The Institute is presenting its research at this year's CeBIT show in Hanover, so don't expect to see this technology in a handset any time soon. But that just gives you plenty of time to come up with even more inventive uses for soundless calling, should it ever hit the mainstream.

[via Cellular News]