Number of speakers of English

The number of speakers of English worldwide is not as easy to calculate as might be imagined. On the one hand, not all countries have accurate census data; and even if they do, they don't necessarily count all the languages spoken by the citizens in their country. On the other hand, one may ask what it means to "speak" English.

Whatever the actual figures it is possible that they are overestimated in the (English speaking) public's mind. A 1998 Harris poll found that, on average, adult Americans believe that just over half (52%) of the world's population speak English. Harris maintains that the real number is probably closer to 20% at maximum.

The numbers
According to Wikipedia, the total number of individuals who speak English either as a first or second language is between 1,800 million and 510 million - a variation of such magnitude that the difficulty in compiling such statistics becomes clear. See also.

Continuing with Wikipedia, if we consider its list of languages by number of native speakers, then the total number of first language speakers is between 328 million and 341 million.

The population of the world is 6,744 billion, which means that the highest possible percentage of English speakers (using the broadest definition) would be 27%, and the lowest 8%. Native English speakers make up around 5% of the world's population on this basis.

The vast majority of native English language speakers live in the US - 215,423,557. Consequently citizens of the USA make up around 65% of the native speaking population.

English in China
A 2012 article in English Today by Bolton and Graddol, quoting a China Daily article, states that around 400 million people in China, approximately a third of the population, are currently learning English. A more precise figure, that of 390.16 million people who had learnt English i.e. studied it at school as a foreign language, is quoted by Wei and Su in the same issue.