Andrew Dalby said this quote

The fact that in the twentieth century a greater proportion of the people in the world could communicate with one another, using English or just a few other languages, appears not to have stopped any wars, nor to have reduced the frequency with which wars have broken out, nor to have made the wars that have broken out less brutal. In fact, several murderous wars have been fought recently among people who speak 'the same language' in real terms.

~ Andrew Dalby

On the basis of this information, it would be possible to argue that if everybody spoke English (or Chinese or Esperanto for that matter) everybody would be at war even more often.

~ Andrew Dalby

It happens all too often - people regret that their language and culture are being lost but at the same time decide not to saddle their own children with the chore of preserving them.

~ Andrew Dalby

If two thousand five hundred languages are to be lost in the course of the twenty-first century, don’t be in any doubt about what that means for us: in each of those two thousand five hundreds cases a culture will be lost.

~ Andrew Dalby