Over two billion people speak English (as of the 2000s), making English the largest language by number of speakers, and the third largest language by number of native speakers. With 300 million native speakers, the United States of America is the largest English-speaking country, and most native speakers of English are US Americans. Additionally, there are 60 million native speakers in the United Kingdom, 29 million in Canada, 25.1 million in Australia, 4.9 million in New Zealand, and 4.7 million in the Republic of Ireland.
England is the home of the English language, while the UK is the largest English-speaking country in Europe. In the European Union, English is one of 24 official languages and is widely used by EU institutions, by a majority of the population in the Republic of Ireland as their first language, and as a second language among much of the EU population.
Estimates that include second-language speakers vary greatly, from 470 million to more than 2 billion.David Crystal calculates that, as of 2003, non-native speakers outnumbered native speakers by a ratio of 3 to 1. When combining native and non-native speakers, English is the most widely spoken language worldwide.
Besides the major varieties of English, such as British English, American English, Canadian English, Australian English, Irish English, New Zealand English, and their sub-varieties, countries such as South Africa, India, Nigeria, the Philippines, Jamaica, and Trinidad and Tobago also have millions of native speakers of dialect continua ranging from English-based creole languages to Standard English. Other countries, such as Ghana and Uganda, also use English as their primary official languages.
As of 2012, India claims to have the world's second-largest English-speaking population. The most reliable estimate is around 10% of its population (125 million people), second only to the US, and is expected to quadruple in the following decade.
There are five countries with a majority of native English speakers that are sometimes described as the "core Anglosphere". They are: the United States of America (at least 231 million), the United Kingdom (60 million),Canada (at least 20 million),Australia (at least 17 million), and New Zealand (4.8 million). 
English is also the primary natively spoken language in the countries and territories of the Republic of Ireland, Jamaica, Trinidad and Tobago, Guyana, The Bahamas, Belize, Grenada, Barbados, the United States Virgin Islands, the Channel Islands, Antigua and Barbuda, Dominica, Bermuda, Saint Vincent and the Grenadines, the Isle of Man, the Turks and Caicos Islands, Saint Kitts and Nevis, the Cayman Islands, Guam, Gibraltar, the British Virgin Islands, Anguilla, the Falkland Islands, Montserrat, Saint Helena, Ascension and Tristan da Cunha, the British Indian Ocean Territory, the Pitcairn Islands, and South Georgia and the South Sandwich Islands.
Although the majority of the world does not speak English, it is considered the diplomatic language due to its widespread presence in developed nations. This has been widely criticized by scholars who believe that other languages should also be considered "diplomatic".
In some countries where English is not the most spoken language, it is an official language. These countries include Botswana, Cameroon (co-official with French), Eswatini (Swaziland), Fiji, Ghana, India, Kenya, Kiribati, Lesotho, Liberia, Malta, the Marshall Islands, Mauritius, the Federated States of Micronesia, Namibia, Nigeria, Pakistan, Palau, Papua New Guinea, the Philippines, Rwanda, Saint Lucia, Samoa, Seychelles, Sierra Leone, Singapore, the Solomon Islands, Sri Lanka, Sudan, South Africa, South Sudan, Tanzania, The Gambia, Uganda, Zambia, and Zimbabwe. There also are countries where in a part of the territory English became a co-official language, in Colombia's San Andrés y Providencia, Hong Kong, Honduras's Bay Islands, and Nicaragua's Mosquito Coast. This was a result of the influence of British colonization and American colonization in these areas.
India has the largest number of second-language speakers of English (see Indian English); Crystal (2004) claims that combining native and non-native speakers, India has more people who speak or understand English than any other country in the world. However, most scholars and research that has been conducted dispute his assertions.Pakistan also has the English language (Pakistani English) as a second official language after the Urdu language as the result of British rule (Raj), making Pakistan the only Islamic country in which English is official. Sri Lanka and the Philippines use English as their second and third official language after Sinhala and Tamil, and Filipino, respectively.
English is one of the eleven official languages that are given equal status in South Africa (South African English). It is also the official language in current dependent territories of Australia (Norfolk Island, Christmas Island and Cocos (Keeling) Islands) and of the United States of America (American Samoa, Guam, Northern Mariana Islands, Puerto Rico (in Puerto Rico, English is co-official with Spanish) and the US Virgin Islands), and Hong Kong Special Administrative Region of the People's Republic of China.
Although the United States federal government has no official languages, English has been given official status by 32 of the 50 US state governments. Furthermore, per United States nationality law, the process of becoming a naturalized citizen of the US entails a basic English proficiency test, which may be the most prominent example of the claim of the nation not having an official language being belied by policy realities.
Although falling short of official status, English is also an important language in several former colonies and protectorates of the United Kingdom, such as Bahrain, Bangladesh, Brunei, Cyprus and the United Arab Emirates.
Because English is so widely spoken, it has often been referred to as a "world language", the lingua franca of the modern era, and while it is not an official language in most countries, it is currently the language most often taught as a foreign language. It is, by international treaty, the official language for aeronautical and maritime communications. English is one of the official languages of the United Nations and many other international organizations, including the International Olympic Committee. It is also one of two co-official languages for astronauts (besides the Russian language) serving on board the International Space Station.
English is studied most often in the European Union, and the perception of the usefulness of foreign languages among Europeans is 67 per cent in favour of English ahead of 17 per cent for German and 16 per cent for French (as of 2012). Among some of the non-English-speaking EU countries, the following percentages of the adult population claimed to be able to converse in English in 2012: 90 per cent in the Netherlands, 89 per cent in Malta, 86 per cent in Sweden and Denmark, 73 per cent in Cyprus, Croatia, and Austria, 70 per cent in Finland, and over 50 per cent in Greece, Belgium, Luxembourg, Slovenia, and Germany. In 2012, excluding native speakers, 38 per cent of Europeans consider that they can speak English.
Books, magazines, and newspapers written in English are available in many countries around the world, and English is the most commonly used language in the sciences with Science Citation Index reporting as early as 1997 that 95% of its articles were written in English, even though only half of them came from authors in English-speaking countries.
In publishing, English literature predominates considerably with 28 per cent of all books published in the world [leclerc 2011][full ] and 30 per cent of web content in 2011 (down from 50 per cent in 2000).
This increasing use of the English language globally has had a large impact on many other languages, leading to language shift and even language death, and to claims of linguistic imperialism. English itself has become more open to language shift as multiple regional varieties feed back into the language as a whole.