Students should not be concerned about any differences between British and American English.
When recording cassettes for students and teachers, I use actors with both American and English voices. They provide a variety of differences in pronunciation and intonation which it is useful to get used to.
But if you ask me if there are structural differences between American English and British English, then I have to tell you, "No, not that you would notice."
Of course, you get these variations of vocabulary that people make much of, and some are listed here. But I would say there is a greater difference between the class and regional dialects within each country than there is between the educated speech of San Francisco and London.
The real problem is to understand a Southerner from the Louisiana bayou country, or a Liverpudlian from Toxteth, or a Glaswegian.
There is the odd word that can cause difficulties. Years ago, teaching a class of teenagers in Montreal, I learnt quickly that what the English call a rubber, the North Americans call an eraser. A rubber in North America is a colloquialism for a condom. Asking a student if I might borrow his rubber was an invitation to loud laughter and coarse comment.
Another student was always late. I asked her if she couldn't get someone to knock her up in the mornings. Collapse of class. In England, it means to wake someone up, but in North America, to get a girl pregnant.
But, I repeat, the differences, the real differences, between British and
American English are slight, and the one borrows from the other constantly. Americans are perhaps more inventive, however. Recently, we have had "zipperwatch", a marvellous word to describe a reporter who is assigned to check on the sex-life of a politician; more recently, "bimbo", an attractive girl of limited intellect.
American English are slight, and the one borrows from the other constantly. Americans are perhaps more inventive, however. Recently, we have had "zipperwatch", a marvellous word to describe a reporter who is assigned to check on the sex-life of a politician; more recently, "bimbo", an attractive girl of limited intellect.
A few, largely time-worn, examples of British/American vocabulary differences (the British version is given first):
caretaker/janitor, council school/public school, public school/private school, dust cart/garbage truck, ex-serviceman/veteran, lift/elevator, fanlight/transom, holiday/vacation, pram/baby-carriage, pig breeding/hog raising, queue/line-up, scribbling-block/scratch-pad, tap/faucet, veranda/porch, timber/lumber
In Romania, some believe that if you toss coins into the river, you’ll have good luck throughout the coming year. Even more impressive: some peasants use December 31st to predict the coming year’s weather by systematically peeling, salting and reading the skins of 12 onions. According to 
Ever hear of dropping a dollop of cream on the floor to ring in the new year with good luck, wealth and peace? Well that’s what some do in Switzerland — it’s thought to bring a year of abundance. (Hey, don’t laugh… provided everyone cleans up his or her dollop, it’s a lot more civilized than screaming along with a trillion other people in Times Square.) Some Swiss also observe the tradition of dressing up in costumes to invoke good spirits and chase evil energies.
The French mix health and wealth and usher in the new beginning with a stack of pancakes. (Note to self: get rich quick scheme no. 145: open an iHop in Paris) Another unique custom in France is kissing under the mistletoe as the clock strikes midnight on New Year’s Eve, sorta like Christmas traditions elsewhere.
In the northern parts of Portugal, children traditionally sing carols as they visit houses where they are given coins and treats. The songs they sing are called janeiros and are said to bring good luck. As in Spain, eating 12 grapes at midnight ensures 12 months of happiness in the coming year.
