The findings are revealed in ‘American and British English: Divided by A Common Language’, by Professor Paul Baker of Lancaster University, published by Cambridge University Press.

The book uses a mixture of human analysis and computerised techniques to spot changes in British and American English from the 1930s to the present day, using large datasets of published writing from a wide range of sources.

It considers spelling differences, words, grammatical classes (eg nouns, verbs and adjectives) and topics and concepts like ‘war’ and ‘danger’.

And it asks how language varieties are changing and if they becoming more similar to one another over time?

Findings include:

• Easy-to-spot ‘surface’ features are holding up – things like the spelling of colour/color or the choice of whether to use pavement or sidewalk. Both sides of the Atlantic are tending to stick to national varieties – although American English has a slight edge overall.
• For more subtle, difficult-to-spot aspects of language, both languages have shown change since the 1930s – and in all cases it is American English which is at the forefront of the change.
• British English seems to be behind by around 30 years or so. These involve aspects like shorter sentences and words (‘that’ replacing ‘which’ for example), combining words with apostrophes (do not becoming don’t), shorter possessive forms (the king’s hand rather than the hand of the king), more use of acronyms.
• Fixed phrases like ‘more or less’, ‘two or three’, ‘for the most part’ and ‘by no means’ are declining, perhaps because there are shorter ways to express them and they come across as clichéd and long-winded.
• A set of adverbs called gradable adverbs like ‘really’, ‘very’, ‘quite’ and ‘rather’ have also declined – to an extent adverbs are less important in language than nouns, adjectives and verbs as they convey subtler shades of meaning.

“And for all the things mentioned above, American English is leading the way,” says Professor Baker. “It’s not clear whether British English is simply following/copying the American trends or is just on the same path, independently so.

“The two languages do have contact with one another, and especially in the UK there is a lot of exposure to American film and TV, so I'm inclined to go more with the idea of British English being influenced by American English".

In addition, language on both sides of the Atlantic, is becoming more informal, personal and conversational.

There is a move towards writing sentences in the active form as opposed to the passive, and higher use of personal pronouns like ‘I’ and ‘me’ (especially in American English).

Many titles such as Mr and Reverend are being dropped from language use.

Words associated with speech like ‘sorry’, ‘please’ and ‘thank you’ are appearing more in written contexts.

Taboo subjects and words are discussed with increasing frequency – including swear words, religious oaths or references to sex and sexuality.

Some aspects of English have become a bit more dramatic or hyperbolic. For example, the word ‘love’ has changed its meaning. It was mostly used to refer to family members or God but it can now refer to anything that we mildly like.

People are trying to appear less authoritarian in their writing. A group of words called modal verbs (would, should, could, must, shall, ought etc) are generally waning, especially the ones which suggest a strong position (e.g. should, shall and must).

“In terms of differences between British and American English, due to the ‘lag’ in adopting some of the changes above, British English might appear a bit old fashioned compared to American English,” says Professor Baker.

There is also a higher use of politeness forms in British English – words like ‘please’, ‘sorry’ and ‘thanks’ – these words are not always used politely though. British people can sometimes use them when they are being rude (for example “I’ll thank you not to do that”, “Please get out”, “Sorry but I don’t agree”) or sarcastic suggesting that orienting to politeness is a more salient aspect of their culture.