More on this & related topics below. (English language level: Upper Intermediate CEF (B2)
According to David Graddol's extensive survey for the British Council, the number of non-native or second language speakers of English now outnumbers those of primary or native speakers. At the same time there is an ever increasing need for speakers of different languages to communicate with each other:
international tourism is growing, but the proportion of encounters involving a native English speaker is declining (1.9). There were around 763 million international travellers in 2004, but nearly 75% of visits involved visitors from a non-English-speaking country travelling to a non-English-speaking
destination. This demonstrates the ... growing role for global English.
(free) Interview with Robert McCrum: The rise of Globish
Recommended Reading: Globish: How the English Language Became the World's Language