Looking at the past is an important step towards understanding the future. Any serious study of English in the 21st century must start by examining how English came to be in the state it is and spoken by those who speak it. What factors have ensured the spread of English?
What does this process tell us about the fate of languages in unique political and cultural contexts? In what domains of knowledge has English developed particular importance and how recently?
English is remarkable for its diversity, its propensity to change and be changed. This has resulted in both a variety of forms of English, but also a diversity of cultural contexts within which English is used in daily life. The
main areas of development in the use and form of English will undoubtedly come from non-native speakers. How many are there and where are they located? And when and why do they use English instead of their first language?
We need to be aware of the different place that English has in the lives of native speakers, second-language users and those who learn it as a foreign language. […]
There are three kinds of English speaker: those who speak it as a first language, those for whom it is a second or additional language, and those who learn it as
a foreign language. Native speakers may feel the language “belongs” to them, but it will be those who speak English as a second or foreign language who will determine its world future.

The Future of English? The English Company (UK) Ltd.
http://www.english.co.uk/FoE/contents/cont.html