I was fiddling with a London Underground ticket machine to purchase a "tube" (subway) ticket upon my arrival here today, and a couple on the next machine over starting asking me questions...in French. Through gestures and pointing to the ticket machine screen display, I figured out that while the screen stated the Oyster card they wished to purchase covered the tram and bus, it did not mention use on the tube. I was experiencing some screen information shortcomings myself in desiring to purchase a zones 1-3 ticket, but only 1-1, 1-2 and 1-4 were offered. So given my prior research on the Oyster card and the incompleteness of our respective ticket machine user interfaces, I assured them that they Oyster card would work for the tube as well.
But this experience struck me later in the day in that we were only able to successfully communicate when we supplemented our verbal attempts at communication with gestures and visual clues. Had they rang me on my phone and asked me the same question, we would gone around in circles with little likelihood of success. This naturally brought me back to one of my favorite topics, IPv6. Speaking French to an English (non-French) speaker is a lot like an IPv6 device trying to communicate with an IPv4 (non-IPv6) device: it will not work!
Of course if I was bi-lingual (analogous to dual-stack) we would have easily and natively communicated. Otherwise, if we had no visual ability, a translator would have been required, analogous to a protocol translation gateway for IPv4-IPv6. But as we know in speech translation, something usually gets "lost in the translation", which is possible in IP communications, especially for sophisticated IP applications like SIP traversing a translation gateway. By the way, the third technology of IPv4-IPv6 co-existence, tunneling, doesn't really apply to our analogy, which would have been more like I had written a note in English, sealed it in an envelope on which delivery instructions were written in French and asked my French friends to deliver it!
The bottom line is that if you want to communicate globally, speak the language! Keep learning and gearing up for IPv6! It's the Internet "language" of the future.