English language has doubled over last century

London: The English language is enjoying unprecedented growth and has nearly doubled in size over the last century.

Researchers at Harvard University and Google found that the language was expanding by 8,500 words a year in the new millennium and now stands at 1,022,000 words.

The rate of increase over the years is shown by the fact that the language has grown by more than 70 per cent since 1950, according to the journal Science.

During the previous half century it only grew by a tenth. But nearly half of the new words are not included in any dictionary and are dubbed lexical "dark matter". They are either slang or invented jargon, reports the Telegraph.

The findings came from the computer analysis of 5,195,769 digitised books (approximately four per cent of all the books ever printed) published between 1800 and 2000.

Jean-Baptiste Michel and colleagues refer to this experiment as "culturomics", and they say their study can be used in fields as diverse as the evolution of grammar, collective memory, the adoption of technology, the pursuit of fame, the effects of censorship and historical epidemiology - just to name a few.

"Now that a significant fraction of the world's books have been digitised, it's possible for computer-aided analysis to reveal undiscovered trends in history, culture, language, and thought," says Jon Orwant, engineering manager for Google Books.