I've personally volunteered for the anthropologist and linguist interviewed in the article sporadically since the 1990s, doing things like OCR'ing early Himalayan journals, setting up and maintaining websites (Digital Himalaya Project, World Oral Literature Project). Eventually I met him for a beer in Cambridge in 2009, shortly before he moved to Yale... great character! I believe he has since moved on to Canada.
That said, as a westerner who has picked up fluent Mandarin (and dabbled in dozes of languages) and who lives nearly full time in China, now raising my own child, I can see the efficacy and likelihood of evolving toward a reduced set of tongues or even a single-tongue. My grandparents spoke English, Croatian, German, and to a lesser extent probably some Russian, Yiddish and Scot. Other than English, only one surviving grandparent (90+) still speaks one of those languages. Similarly on my wife's side, her family have learned and forgotten Arabic and Vietnamese.
If indeed over hundreds of years the world does converge toward a single tongue, I would be surprised if Mandarin Chinese is not a serious candidate: offering simple grammar, huge and well dispersed population, with a pluralistic and pragmatic approach to culinary and other cultural acquisitions from integrated populations. The biggest issue is the number of characters, however a common international subset is perhaps emerging, largely through shared manufacturing supply chains, software interfaces, public signage and media.