Another incremental step. The "science" of translating one human language to another was once thought a trivial task for computers, but it turned out more "art" was needed. Lots of text-to-text translators exist, which succeed to varying degrees.
With the addition of voice recognition to mobile devices, it is to be expected that voice-to-voice translators would come along. Of course, voice recognition apps are still far from perfect even when working within one language.
One of the wilder incremental steps, at least to me, is "augmented reality" translators like Word Lens. Word Lens uses the same kind of OCR (optical character recognition) found in text scanners to read signs. The app then substitutes translated text in the mobile device's screen. That is, one can hold up a smartphone to a sign in a foreign language and get a translation on the smartphone screen, as though one were looking through a window at the native text—and the translated text looks like the original sign!
Predictably, Word Lens found its way onto Google Glass. Some day in the future, one may find oneself housebound if one's visor breaks down. No more GPS signs in virtual space, no translations, no way to interface with computers in stores and elsewhere...