Approximately 330 to 360 million people speak English as their first language. The United States has the most native speakers at 258 million. Additionally, there are 60 million native English speakers in the United Kingdom, 19 million in Canada, 16.5 million in Australia, 4.5 million in Ireland, and 3.8 million in New Zealand. Other countries also use English as their primary and official languages.
Estimates that include second language speakers vary greatly, from 470 million to more than 1 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 American English, British English, Canadian English, Australian English, Irish English, New Zealand English and their sub-varieties, countries such as South Africa, India, the Philippines, Jamaica and Nigeria also have millions of native speakers of dialect continua ranging from English-based creole languages to Standard English.
There are six large countries with a majority of native English speakers that are sometimes grouped under the term Anglosphere. In numbers of English speakers they are: the United States (at least 231 million), the United Kingdom (60 million), Canada (at least 20 million), Australia (at least 17 million),, Ireland (4.2 million) and New Zealand (3.8 million). 
English is also the primary natively spoken language in the countries and territories of Anguilla, Antigua and Barbuda, the Bahamas, Barbados, Belize, Bermuda, the British Indian Ocean Territory, the British Virgin Islands, the Cayman Islands, Dominica, the Falkland Islands, Gibraltar, Grenada, Guam, Guernsey, Guyana, the Isle of Man, Jamaica, Jersey, Montserrat, Pitcairn Islands, Saint Helena, Ascension and Tristan da Cunha, Saint Kitts and Nevis, Saint Vincent and the Grenadines, South Georgia and the South Sandwich Islands, Trinidad and Tobago, and the Turks and Caicos Islands.
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), the Federated States of Micronesia, Fiji, Ghana, Hong Kong, India, Kenya, Kiribati, Lesotho, Liberia, Malta, the Marshall Islands, Mauritius, 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, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe. There also are countries where in a part of the territory English became a co-official language, e.g. Colombia's San Andrés y Providencia and Nicaragua's Mosquito Coast. This was a result of the influence of British colonization in the area.
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.
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 Island) and of the United States (American Samoa, Guam, Northern Mariana Islands, Puerto Rico (in Puerto Rico, English is co-official with Spanish) and the US Virgin Islands), and the former British colony of Hong Kong. (See List of countries where English is an official language for more details.)
Although the United States federal government has no official languages, English has been given official status by 32 of the 50 US state governments. 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 percent in favour of English ahead of 17 percent for German and 16 percent 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 percent in the Netherlands, 89 percent in Malta, 86 percent in Sweden and Denmark, 73 percent in Cyprus and Austria, 70 percent in Finland, and over 50 percent in Greece, Belgium, Luxembourg, Slovenia, and Germany. In 2012, excluding native speakers, 38 percent 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 percent of all books published in the world [leclerc 2011] and 30 percent of web content in 2011 (down from 50 percent 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.