English today is probably the third largest language by number of native speakers, after Mandarin Chinese and Spanish.
However, when combining native and non-native speakers it is probably the most commonly spoken language in the world, though possibly second to a combination of the Chinese languages (depending on whether or not distinctions in the latter are classified as "languages" or "dialects").
Estimates that include second language speakers vary greatly from 470 million to over a billion depending on how literacy or mastery is defined and measured. Linguistics professor David Crystal calculates that non-native speakers now outnumber native speakers by a ratio of 3 to 1.
The countries with the highest populations of native English speakers are, in descending order: United States (215 million), United Kingdom (61 million), Canada (18.2 million), Australia (15.5 million), Nigeria (4 million), Ireland (3.8 million), South Africa (3.7 million), and New Zealand (3.6 million).
Countries such as the Philippines, Jamaica and Nigeria also have millions of native speakers of dialect continua ranging from an English-based creole to a more standard version of English. Of those nations where English is spoken as a second language, India has the most such speakers ('Indian English').
Crystal claims that, combining native and non-native speakers, India now has more people who speak or understand English than any other country in the world.