[geebee]

There's another possibility: everyone is bilingual in "Universal" (English) and "local language X". As long as you have a few thousand people, speak whatever you like.

English really isn't the greatest choice for international language - it is fairly idiomatic - but it wasn't really a "choice" anyway. Still, it appears to be heading for international language status. I read that conferences in Asia, where native speakers of English are less than 1% of participants, often just use English to deal with the fact that there are hundreds of languages represented at the conference.

At the same time, many (admittedly well educated) countries are proving that you can use your native language and English. Based on my most recent trip, I'd say it's easier to get clear directions in English from a bus driver in Stockholm than in San Francisco.

So ironically, the widespread use of English could actually be a boon for obscure languages. You can preserve one for cultural identity, and use English for business. That said, this model is probably not going to help the last 500 speakers in a remote village without running water.