Ditto to that. I've no problem with English as lingua franca. It started to gain that status long before. Jerome K Jerome wrote about the spread of English a hundred years ago in "Three Men on the Bummel":

"Shakespeare and Milton may have done their little best to spread acquaintance with the English tongue among the less favoured inhabitants of Europe. Newton and Darwin may have rendered their language a necessity among educated and thoughtful foreigners. Dickens and Ouida (for your folk who imagine that the literary world is bounded by the prejudices of New Grub Street, would be surprised and grieved at the position occupied abroad by this at-home-sneered-at lady) may have helped still further to popularise it. But the man who has spread the knowledge of English from Cape St. Vincent to the Ural Mountains is the Englishman who, unable or unwilling to learn a single word of any language but his own, travels purse in hand into every corner of the Continent. One may be shocked at his ignorance, annoyed at his stupidity, angry at his presumption. But the practical fact remains; he it is that is anglicising Europe. For him the Swiss peasant tramps through the snow on winter evenings to attend the English class open in every village. For him the coachman and the guard, the chambermaid and the laundress, pore over their English grammars and colloquial phrase books. For him the foreign shopkeeper and merchant send their sons and daughters in their thousands to study in every English town. For him it is that every foreign hotel- and restaurant-keeper adds to his advertisement: "Only those with fair knowledge of English need apply."
Did the English-speaking races make it their rule to speak anything else than English, the marvellous progress of the English tongue throughout the world would stop. The English-speaking man stands amid the strangers and jingles his gold.
"Here," cries, "is payment for all such as can speak English."
He it is who is the great educator. Theoretically we may scold him; practically we should take our hats off to him. He is the missionary of the English tongue."

But I wouldn't want English could to replace all other languages, of course. The world would lose a great part of of its charm and diversity. Not sure that could ever happen but who knows...