You'll able to converse quickly/fluently/easily in real time with someone who you don't share a language with with speech recognition/machine translation/speech synthesis.
Spaceship Earth at Epcot (Disney World) actually featured this in its 1994 update (coincidentally, sponsored by and prominently featuring AT&T). (The overall theme of the ride, under AT&T's sponsorship, was the history of communications-- ultimately culminating in a scene depicting a vision of the future of global communications thanks to the internet.)
It may be the only thing out of that scene that hasn't really come to fruition yet. They show video calling-- we have that. They show telemedicine-- we have that. But it turns out that real-time, speech to speech translation is Really Hard, even as text-to-text translation has gotten massively better over the past few years.
