Edited sentence: A working knowledge of English has become a requirement in a number of fields, occupations and professions such as medicine and computing; as a consequence over a billion people speak English to at least a basic level (see English language learning and teaching).Following British colonization in North America, it is the dominant language in the United States, whose growing economic and cultural influence and status as a global superpower since World War II have significantly accelerated the language's adoption across the planet.It is also one of six official languages of the United Nations.Its spread beyond the British Isles began with the growth of the British Empire, and by the late nineteenth century its reach was truly global.Linguists such as David Crystal recognize that one impact of this massive growth of English, in common with other global languages, has been to reduce native linguistic diversity in many parts of the world, most particularly in Australasia and North America, and its huge influence continues to play an important role in language attrition.Modern English, sometimes described as the first global lingua franca, is the dominant international language in communications, science, business, aviation, entertainment, radio and diplomacy.Similarly, historical linguists, aware of the complex and fluid dynamics of language change, are always aware of the potential English contains through the vast size and spread of the communities that use it and its natural internal variety, such as in its creoles and pidgins, to produce a new family of distinct languages over time