Do they still use and understand those expressions?

English as a Second Language English Vocabulary, Grammar and Idioms
1

I am reading the page englishclub.com/english-language-history.htm in which they wrote:

From around 1600, the English colonization of North America resulted in the creation of a distinct American variety of English. Some English pronunciations and words “froze” when they reached America. In some ways, American English is more like the English of Shakespeare than modern British English is. Some expressions that the British call “Americanisms” are in fact original British expressions that were preserved in the colonies while lost for a time in Britain (for example trash for rubbish, loan as a verb instead of lend, and fall for autumn; another example, frame-up, was re-imported into Britain through Hollywood gangster movies)

Some expressions that the British call “Americanisms” are in fact original British expressions that were preserved in the colonies while lost for a time in Britain → So does it mean those expressions are from British? Then can you tell me do they still use and understand those expressions? And why do they stop using those expressions while American still do.

Thanks a bunch.

2

Originally used by British speakers, yes. “from British” sounds a bit odd since there is not and never has been a language called “British”.

I assume by “they” you mean British people. British people generally do not use Americanisms. If they did, they would not call them Americanisms. However, most British people understand many Americanisms. Often this is because of wide exposure to American culture, but sometimes the meaning is obvious anyway. For example, it’s obvious what “loan” as a verb means. Some words and expressions that were once Americanisms have been imported (or re-imported) into British English, and this trend continues.

In most cases the answer is probably not known. It is usually very hard to determine why a word goes out of fashion.