the Babel fish

The Babel Fish (from Hitchiker's guide to the galaxy) is a small yellow fish you put in your ear to translate other languages. It swims through your ear canal into your brain, where instead of feeding off of your brain, it does something incredible. It actually feeds off of other's brain waves and converts them into coherent thoughts of your language. Contrary to popular belief, you cannot watch foreign language films or read foreign text, even with the babel fish, since it only converts from active brainwave that are in the same room as you, not a language that's been recorded or from the written word.