English is the international language, even among the bad guys. When a nuclear expert from North Korea talks to his counterpart in Iran, they speak English.
Years ago, I knew a french-speaking guy in Geneva who regularly communicated with another french-speaking guy in Lyon by email in english.
There was no real reason for him to do it that way that I can figure, other than it was across a border and via the internet (where english has been since its inception the lingua franca).