The globalisation of the language is causing it to fragment.
On 5th September, 1780 John Adams, who was later to succeed George Washington as President of the United States, wrote a letter to Congress in which he foresaw an international role for the English language, comparable to that of Latin in the past and French in the 18th century. He supported his argument by pointing to the relationship between the form of government, the population and its language: a free Republic is based on political discourse (eloquence) and therefore in such a context its language is refined and purified (the explicit reference being Athens and Rome). The United States, with its democracy and its demographics, would turn English into a global language.
This forecast has turned out to be correct: English is one of the most widely spoken languages in the contemporary world, but the global diffusion of English has not meant the spread of the classic form of the language Adams was referring to, but rather the adoption of internally diversified versions.
United States English was the first to claim its independence from the British norm. The differences are well known, and particularly obvious in the phonetics and vocabulary. Similar situations have arisen in other nations where English became the mother tongue following colonisation: Ireland, Canada, a few Caribbean countries, Australia and New Zealand.