If you're travelling abroad, or facing a language barrier, the Google Translate app can help a lot. Not perfect, but good enough to get you there. Perfect also for students of English who need to improve their pronunciation getting instant feedback (if GT can't understand you, chances are a native won't either).

Google Translate app for smartphones comes with a real time conversation mode (as you can see in this other video), but it now also includes Word Lens, a visual translator that lets you translate text and signs directly through your phone viewer. Just click on the photo mode (camera icon), point your phone at the text and the image will change from one language to another before your very eyes. But enough about it, download the new "Google Translate" app on your phone (or update it) and see it for yourself.