A video and song about 30 countries with about a million (or more) speakers of English. In these countries English also has some official status. This is why countries like China which has millions of English learners are not listed. Nor are countries like Antigua which has fewer than a million speakers.
This video shows the vast spread of the British Empire and the legacy of the English language.
The maps come mostly from the CIA, actually, available for download from the Perry-Casteneda Map Library at the University of Texas at Austin.
The source for this is David Crystal's book ENGLISH AS A WORLD LANGUAGE.