Most ELT specialists nowadays insist that we should not make this clear distinction between American and British English and, instead, we should teach our students what recent trends call International English.
Honestly, I understand them and I think we should always try to teach our students more than just one version of English. On the other hand, saying that English is becoming more and more international and that we can forget about the distinction between both types of English might not be completely true.
I’ve recently come across a very interesting blog where I found a post with a short video proving that even native speakers have some problems when they have to face the differences between the American and British English.
In the video below, you’ll see Emma Watson (Harry Potter’s Hermione Granger) talking to David Letterman about those cultural differences she had to face when she started college in the US.
This is, IMHO, crucial in order not to neglect explaining those differences to our students, even if we decide our teaching is gonna be based on the so called International English.
After all, a rubber might be a simple school object in the UK, whereas in the US it might have a completely different meaning. And that’s just one very interesting example of the confusions we might create by not considering the differences in British and American English in our teaching.