Michele Gazzola in The Guardian: The emergence of English as the predominant (though not exclusive) international language is seen by many as a positive phenomenon with several practical advantages and no downside. However, it also raises problems that are slowly beginning to be understood and studied.
The most important challenge is that of fairness or “linguistic justice”. A common language is a bit like a telephone network: the more people know a language, the more useful it becomes to communicate. The question of fairness arises because individuals face very different costs to access the network and are on an unequal footing when using it. Those who learn English as a second language incur learning costs, while native speakers can communicate with all network members without incurring such costs. It’s like getting the latest smartphone model and sim card with unlimited data for free.
François Grin, of the University of Geneva, estimates that western European countries spend between 5% and 15% of their education budget on foreign language teaching. In the EU, most of these resources go to the teaching of a single language, English. More here.